On the synchrony, variation and diachrony of adverbial exceptive clauses in Polish

In this article, I examine the synchrony and the diachrony of adverbial exceptive clauses in Polish headed by the complementizer chyba że ‘unless’. Synchronically, I argue that chyba-że-clauses are JudgeP modifiers in the sense claimed by Krifka (to appear) and Frey (2016; 2020; to appear(a); to appear(b)). Diachronically, I provide an analysis according to which chyba że ‘unless’ is treated as a morphologically complex C-head that developed out of the preposition chyba ‘except’ and the declarative complementizer że ‘that’ in Middle Polish (1543–1765).


Introduction
Consider the corpus example given in (1) taken from Present-day Polish: (1) (NKJP, Dziennik Zachodni, 30/12/2004) Dzisiaj po południu mogą wyjść na wolność, chyba że sąd today after midday.loc can.3pl go:out.inf on freedom.acc unless court zdecyduje inaczej. decide.3sg differently 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' (1) consists of a matrix clause and an embedded clause introduced by the complementizer chyba że corresponding to the English complementizer unless. It has been referred to in the literature as an exceptive clause 1 (cf. Geis 1973, Brée 1985, von Fintel 1992, Declerck & Reed 2000or Fretheim 2006). In general, exceptives are used to express exceptions to generalizations, cf. Reinhart (1991), von Fintel (1993), Moltmann (1995), Arregui (2006), Álvarez (2008), to name but a few. Concretely, (1) can be paraphrased as follows: The prisoners will be released from the prison except that/if the court will/would take a different decision. To put it differently: Let us assume Q to be the proposition of the matrix clause, and P the proposition of the subordinate clause. The subordinate relation between Q and P chyba że establishes (= Q chyba że P) is 'Q in a case other than P'. The major objective of this article is to to examine chyba-że-clauses at the syntax-semantics interface both from a synchronic and a diachronic perspective. Remarkably, Blümel & Pitsch (2019: 5) argue that the meaning of the embedded clause given in (1) cannot be 1 Of course, in Polish exist other adverbial clauses that can be labeled, at least from a semantic point of view, as exceptive clauses, as well. Accordingly, we can rephrase the embedded clause given in (1), for instance, by using one of the conditional complementizers and by negating the embedded proposition, as illustrated in the following example: (i) Dzisiaj po południu mogą wyjść na wolność, jeśli sąd nie zdecyduje inaczej.
today after midday can.3pl go:out.inf on freedom.acc if court neg decide.3sg differently 'They are allowed to be released from the prison today afternoon, if the court will not take a different decision.' In the present study, I restrict myself to exceptive clauses in which the preposition chyba 'except' has been incorporated into the clause structure. However, I will compare their syntax with negated conditional clauses headed by the inherent conditional complementizer jeśli 'if' in order to capture their striking peculiarities (for more details, see Section 2.2). Interestingly, Fretheim (2006) argues that unless is truth-conditionally identical to if … not, although Geis This article is structured as follows. To begin with, I discuss the most important syntactic and semantic properties of exceptive clauses in Polish headed by the complementizer chyba że 'unless'. This is provided in Section 2. Section 3 is concerned with exceptive clauses in older stages of Polish. In Section 4, I provide a novel account of how chyba-że-clauses came into being and account for where their syntactic and semantic properties pointed out in Section 2 come from. In doing so, I also show how chyba 'except' and że 'that' developed into a complex complementizer, giving rise to an exceptive interpretation. Finally, I conclude the findings in Section 5.

Exceptive clauses in Present-day Polish
The main aim of this section is to examine the syntax and semantics of exceptive clauses in Present-day Polish headed by the morphologically complex C-head chyba że 'unless'.
However, first it needs to be proven that chyba że is a frozen complex complementizer.
In principle, one could intuitively argue that chyba is employed either as a preposition (= 'except') or as a discourse particle (= 'presumably') taking a wide scope over the embedded że-clause. As prepositions can select for CPs and discourse particles usually scope over propositions, such an analysis would not be surprising. As it turns out below, though, this view cannot be upheld altogether. Several empirical arguments suggest to reject this kind of analysis.
Firstly, as has been observed by Skibicki (2007: 272), among many others, chyba cannot be dropped: (2) *Dzisiaj po południu mogą wyjść na wolność, że sąd zdecyduje today after midday.loc can.3pl go:out.inf on freedom.acc that court decide.3sg inaczej. differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' The contrast between (1) and (2) illustrates already that chyba cannot be analyzed as a discourse particle in (1). Discourse particles are usually considered optional modal elements modifying speech acts and expressing speaker's attitude towards what is embedded. If chyba in (1) were a discourse particle, one should be able to drop it. This is not the case, though.
Secondly, the declarative complementizer że 'that' cannot be replaced by its counterpart iż 'that' occurring mainly in higher register texts: 2 (3) *Dzisiaj po południu mogą wyjść na wolność, chyba iż sąd today after midday.loc can.3pl go:out.inf on freedom.acc unless court zdecyduje inaczej. decide.3sg differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' Again, if chyba and że would constitute two distinct heads, że would be expected to be replaceable with iż. One of the anonymous reviewers objects that occasionally one can find cases in which chyba and iż co-occur: (4) odpowiedzialność samorządu terytorialnego za realizację przyznanych responsibility authority.gen local for realization.acc assigned mu zadań, chyba iż ustawowo prawo to mają przyznane inne him.dat tasks except that constitutionally right this have.3pl granted other podmioty bodies 'the responsibility of the local authority for the realization of the tasks assigned to it, except when constitutionally this right is granted to other bodies' I agree that such examples can be attested, but they occur very seldom. A search query in Narodowy Korpus Języka Polskiego yields only 12 occurrences. As native speaker of Polish, I would judge all of them, including (4), as questionable. It might be that authors of these 12 2 In older stages of Polish, in particular in Old Polish, że was used to add emphasis. To introduce embedded clauses one usually employed iże 'that' which was originally a relative clause marker (cf. Meyer 2017) and which in some contexts lost the initial vowel i becoming homophonous with the focus particle. Traces of this development can still be observed in Present-day Polish cases in which both elements co-occur: (i) (Bański 2000: 99, ex In (i), the first że is a declarative complementizer introducing a subordinate clause; the second że, in turn, is a focus particle merging with the mobile inflection auxiliary marked for the second person plural. For more details, the interested reader is referred to Decaux (1955), Bański (2000;2001), Migdalski (2016: 156-157  Thirdly, if chyba and że in (1) are taken together to constitute a morphologically complex complementizer expressing an exception, we do not expect chyba to occur in combination with other clause types having a declarative sentence mood in the sense claimed by Portner (1997;, and giving rise to an exceptive meaning. This prediction is borne out: (5) (NKJP, Głos Siemiatycz, 2008/10/29) Jednak chyba jeśli pojawiał się uczeń mający problem z however presumably if appear.l-ptcp.sg.m.hab refl student having problems with narkotykami, to był to raczej ewenement w skali szkoły? drugs then be.l-ptcp.sg.m this rather sensation in scale school.gen 'However, presumably if a student appeared who had problems with drugs, then this would rather be a sensation by the standards of this school?' In (5), chyba is used as a discourse particle meaning 'presumably' taking scope of the whole conditional clause headed by jeśli 'if'. But taken together they do not trigger an exceptive meaning.
Instead each of them has to be interpreted on its own. 4 Finally, the dependency of the subordinate clause given in (1) cannot be attributed only to chyba, as że cannot be omitted, either: (6) *Dzisiaj po południu mogą wyjść na wolność, chyba sąd today after midday.loc can.3pl go:out.inf on freedom.acc except court zdecyduje inaczej. decide.3sg differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' 3 Notice that the co-occurence of chyba and iż does not contradict the analysis proposed in this article, quite the contrary: It strongly supports the observation that a preposition and a declarative complementizer can develop into a morphologically complex complementizer introducing an adverbial clause. In Present-day Polish że and iż introduce mainly complement clauses, whereby the latter is favored in higher registers. This might explain why it was not incorporated into the exceptive clause structure, instead of że. Furthermore, I consulted some younger and older native speakers of Polish and presented them the example given in (1) twice: once with chyba że and another time with chyba iż. All of them -more or less -disliked the latter variant, and considered the former variant most natural. A study based on questionnaire data would shed more light on this variation. I thank one of the anonymous reviewers for an insightful discussion on this issue. 4 I thank one of the anonymous reviewers who drew my attention to this issue.
Cross-linguistically, it has been observed that particles of different kinds can grammaticalize into subordination conjunctions. A case in point is the German causal complementizer zumal 'the more so as' / 'especially since', which developed out of the use as a focus particle in the 17th century: German (Jędrzejowski 2017: e25, ex. 7-8) a. Eine Schwierigkeit stellt für die Asylbewerber zur Zeit die a difficulty constitute.3sg for the applicants:for:asylum to:the time the Sprachbarriere dar, zumal keiner Deutsch spricht. language:barrier vptcl the:more:so:as nobody German speak.3sg 'A difficulty for the applicants for asylum constitutes at the moment the language barrier, the more so as none of them can speak German.' b. Sorgfältig verschloß er daher jeden Abend seine Thüren und Läden, carefully close.3sg.pst he therefore every evening his doors and shops zumal da nur einer seiner Sklaven dienstfähig war. foc.ptcl because only one of:his slaves fit:for:duty be.3sg.pst 'Therefore he was closing his doors and shops every evening carefully, in particular because only one of his slaves was fit for duty.' Accordingly, the subordinate conjunction zumal triggering verb-final position in (7a) is assumed to have evolved from the combination of the additive scalar focus particle zumal and a causal conjunction, as exemplified in (7b). Over time zumal itself began to be used as a subordinate C-head and to trigger the verb final-position without losing its focus interpretation (for a more detailed synchronic and diachronic analysis of zumal-clauses in German, the interested reader is referred to Eberhardt 2017). As (6) convincingly shows, exceptive chyba-że-clauses have not reached this development stage and the declarative complementizer że 'that' is still needed to express an exceptive meaning.
Based on what we have seen so far, we can conclude that exceptive clauses in Polish are introduced by the morphologically complex complementizer chyba że 'unless'. Its complexity is traced back to two functional heads, the preposition chyba 'except' and the declarative complementizer że 'that'. None of these elements can be replaced or omitted if one intends to express an exceptive meaning. In this context, it is reasonable to investigate syntactic and semantic properties of chyba-że-clauses in Present-day Polish. Before I elaborate on this issue in more detail, I briefly examine the variation of exceptive clauses.

Variation
As pointed out above, exceptive clauses in Present-day Polish are headed by the morphologically complex C-head chyba że 'unless'. I repeat the example given in (1) as (8) below: Dzisiaj po południu mogą wyjść na wolność, chyba że sąd today after midday.loc can.3pl go:out.inf on freedom.acc unless court zdecyduje inaczej. decide.3sg differently 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' The exceptive clause is finite. It consists of the finite perfective verb zdecyduje 'will decide' marked for the indicative mood. It is a preferred pattern in Present-day Polish. However and interestingly enough, the conditional clitic by can attach to chyba że: 5 (9) Dzisiaj po południu mogą wyjść na wolność, chyba że-by sąd today after midday.loc can.3pl go:out.inf on freedom.acc unless-cond court zadecydował inaczej. decide.l-ptcp.sg.m differently 'They are allowed to be released from the prison today afternoon, unless the court would take a different decision.' The presence of the conditional morphology on the complementizer triggers a morphological change. It turns the finite verb into an l-participle, a common Slavic participle form inflected for number and gender (for more details on complex tense forms in Slavic languages, see Migdalski 2006). Semantically, using by the speaker distances himself/herself from the exception introduced in the embedded clause, and expresses a commitment to a proposition that (s)he may feel safer to defend (cf. Krifka to appear). Although (9) is grammatical in Present-day Polish, it is not used as often as its counterpart with indicative morphology is.
Remarkably, exceptive chyba-żeby-clauses do not force by to occur adjacent to że 'that'. It can also appear lower in the exceptive clause structure, i.e. either between the subject and the l-participle or on the l-participle itself, as, again, a slightly modified version of (1) shows (see Borsley & Rivero 1994 for more details on mobile inflection in Polish): (10) Dzisiaj po południu mogą wyjść na wolność, chyba że sąd (by) today after midday.loc can.3pl go:out.inf on freedom.acc unless court cond zadecydował (-by) inaczej. decide.l-ptcp.sg.m-cond differently 'They are allowed to be released from the prison today afternoon, unless the court would take a different decision.' The different position of the conditional morpheme by does not give rise to two distinct interpretations, and the exceptive meaning remains unchanged. Taken all together, we end up with three patterns marking an exception and containing the inherent exceptive complementizer chyba że 'unless': (13) a. chyba że + indicative mood b. chyba żeby + l-participle c. chyba że + l-participle-(by) All of them express a case in which an exception to a preceding (or following) statement will or may exist. As for (13a), I take chyba że to be a morphologically complex C-head occupying a single syntactic position. The second variant given in (13b) does not deviate from (13a). The only difference is that the conditional clitic by moves from a lower position and attaches to the C-head. Based on Migdalski (2006), I assume by to be a head base-generated in MoodP. Finally, when by occurs together with an l-participle, it is the l-participle that raises to by: In the next two sections, I examine exceptive clauses in Polish adhering to the view that they should not be considered negative conditionals, and show that chyba-że-clauses have the status of peripheral adverbial clauses in the sense claimed by Frey (2012;; to appear(a)). In doing so, I focus on (13a), i.e. the pattern with indicative morphology, as it is the most common pattern in Present-day Polish.

Exceptive clauses ≠ negated conditionals
The main objective of this section is to figure out how chyba-że-clauses differ from negated conditional clauses headed by the subordinator jeśli 'if'. There are several reasons why negated jeśliconditionals appear to be the most suitable adverbial clause type to be compared with exceptive clauses: i) they are adverbial clauses, ii) they exhibit mood alternation, and iii) -most importantly -they encode exceptions, i.e., the semantics of negated jeśli-conditionals is closely related to the semantics of exceptive chyba-że-clauses (cf. Clark-Clark 1977: 457;Brée 1985;Comrie 1986 Left periphery: One of the differences refers to the possibility of topicalization or focalization.
Whereas chyba-że-clauses are strongly dispreferred on the left periphery of the matrix clause, negated jeśli-conditionals exhibit no restrictions in this respect: (15) a. *Chyba że sąd zdecyduje inaczej, dzisiaj po południu mogą unless court decide.3sg differently today after midday.loc may.3pl wyjść na wolność. go:out.inf on freedom.acc Intended structure: 'Unless the court will take a different decision, they are allowed to be released from prison today afternoon.' b. Jeśli sąd nie zdecyduje inaczej, dzisiaj po południu mogą if court neg decide.3sg differently today after midday.loc may.3pl wyjść na wolność. go:out.inf on freedom.acc 'If the court doesn't take a different decision, they will be allowed to be released from the prison today afternoon.' A similar observation has been made by Dancygier (1985), who argues that Polish exceptive clauses -as opposed to their English counterparts -cannot be fronted: (16) (Dancygier 1985: 71, ex. 22a-b) a. Unless I am very much mistaken, she is Spanish. b. *Chyba że się mylę, ona jest Hiszpanką. unless refl be:mistaken.1sg she be.3sg Spanish Intended structure: 'Unless I am very much mistaken, she is Spanish.' If one is inclined to assume adverbial clauses to be derived by movement of an operator to the left periphery, as has been suggested in Geis (1970), Citko (2000) Bhatt & Pancheva (2006), Haegeman (2012), to name but a few, one could argue that movement of an exceptive operator to the left periphery is blocked in Polish by an intervening element.
Non-assertive speech acts -questions: Another difference can be observed with regard to root questions. Only jeśli-conditionals can be in the scope of a question operator. Chyba-że-clauses are prohibited in environments associated with root questions: a. *Mogą dzisiaj po południu wyjść na wolność, chyba że sąd may.3pl today after midday.loc go:out.inf on freedom.acc unless court zdecyduje inaczej? decide.3sg differently Intended meaning: 'Will they be allowed to be released from the prison today afternoon, unless the court doesn't take a different decision?' b. Mogą dzisiaj po południu wyjść na wolność, jeśli sąd nie may.3pl today after midday.loc go:out.inf on freedom.acc if court neg zdecyduje inaczej? decide.3sg differently 'Will they be allowed to be released from the prison today afternoon, if the court doesn't take a different decision?' This contrast illustrates that chyba-że-statements presuppose assertive force in the matrix clause, whereas their jeśli-nie-counterparts exhibit no illocutionary restrictions, leading to the conclusion that the exceptive clause cannot be part of a root question. 6 Declerck & Reed (2000: 224) illustrate a similar contrast while discussing the semantics of nonirrealis unless-clauses in English (see also  Haegeman (2003: 322) shows -mainly based on conditional clauses in English -that they can be divided into two larger groups: i) event conditionals and ii) premise conditionals. Only the former, which are integrated into the host clause, however, can be in the scope of an interrogative operator. Accordingly, event conditionals are taken to be central adverbial clauses, while premise conditionals are treated as peripheral adverbial clauses. Frey (2012;; to appear(a)) observes a similar contrast with respect to adverbial causal clauses in German, and claims that adverbial clauses that cannot become part of a question should be analyzed either as peripheral or as disintegrated adverbial clauses in the typology advocated by Haegeman (2003;. It follows then that chyba-że-clauses cannot be central adverbial clauses, and at the same time the example (17a) illustrates that they cannot be considered disintegrated adverbial clauses either, as they clearly depend on the assertive force of the matrix clause.
The focus particle tylko 'only': Geis (1973: 245-7) observes for English that whereas if-notclauses can combine with the focus particle only, unless-clauses cannot: (19) (Geis 1973: 245, ex. 65a-b) a. I will phone you tomorrow only if you don't phone me today. b. *I will phone you tomorrow only unless you phone me today.
Polish patterns with English: (20) a. Dzisiaj po południu mogą wyjść na wolność, tylko jeśli sąd today after midday.loc can.3pl go:out.inf on freedom.acc only if court nie zdecyduje inaczej. neg decide.3sg differently 'They are allowed to be released from the prison today afternoon, only if the court won't take a different decision.' b. *Dzisiaj po południu mogą wyjść na wolność, tylko chyba że sąd today after midday.loc can.3pl go:out.inf on freedom.acc only unless that zdecyduje inaczej. court decide.3sg differently Intended meaning: 'They are allowed to be released from the prison today afternoon, only unless the court will take a different decision.' Geis (1973) argues that that the ungrammaticality of (19b) can be accounted for by postulating some constraint on lexical insertion of unless. This constraint seems to follow from the fact that whereas unless and chyba że express an exception to the validity of the matrix proposition, if … not and jeśli … nie, on the other hand, specify a condition for the matrix proposition. Now, the use of focus particles, i.e. only in English and tylko in Polish, presupposes the existence of a unique condition. This unique condition determines the possible world in which the matrix proposition is true. This is not the case in the exceptive clause where it is the matrix predication that determines the world in which the embedded proposition (= exception) is valid (cf. Brée 1985 andDeclerck &Reed 2000). What is interesting about the focus particles is that they cannot occur within the matrix clause. In this context, the picture does not deviate from that one above: b. *Dzisiaj po południu mogą tylko wyjść na wolność, chyba że today after midday.loc can.3pl only go:out.inf on freedom.acc unless sąd zdecyduje inaczej. court decide.3sg differently Intended meaning: 'They are allowed to be released from the prison today afternoon, only unless the court will take a different decision.' These contrasts clearly illustrate that exceptive clauses -contrary to negated conditionalscannot be in the scope of selected matrix clause operators. This, again, leads to the conclusion that exceptive clauses must attach at a higher structural position of the matrix clause.
Emotive predicates: It is well-known that conditional clauses can be used instead of declarative complement clauses occupying one of the argument slots of a matrix verb. Concretely, in (23a) the emotive matrix verb wnerwiać 'annoy' selects two arguments: The internal argument is the personal pronoun mnie 'me' marked for the Accusative case, the external argument, in turn, is a subject clause headed by the conditional complementizer jeśli 'if' (cf. Williams 1974;Fabricius-Hansen 1980;Pullum 1987;Quer 2002;Hinterwimmer 2010;Thompson 2012;Onea 2015; Schwabe 2016, among many others, for possible analyses): What negated factual conditionals express here is a result or a fact. Since this meaning is not compatible with the inherent exceptive complementizer, the ill-formedness of (27b) straightforwardly follows.
A final note is in order here about variable binding. The received wisdom has it that if a quantified NP can bind into a subordinate clause, it indicates that the dependent clause is integrated into its host clause. Accordingly, we expect chyba-że-clauses to disallow variable binding. However, (28) yields the opposite result: Prawie [każdy pacjent] i może opuścić szpital, chyba że jego i lekarz zadecyduje nearly every patient may.3sg leave.inf hospital unless his doctor decide.3sg inaczej. differently 'Almost every patient may leave the hospital, unless his doctor will take a different decision.' This is surprising if we assume a quantifier to be able to bind an agreeing pronoun in the subordinate clause iff the quantifier c-commands the pronoun. Correspondingly, the exceptive clause in (28) is c-commanded by the quantified expression, i.e. by każdy pacjent 'every patient', which occupies the matrix Spec,TP position. Such cases clearly speak, at least prima facie, against the analysis proposed in the present article according to which chyba-że-clauses are taken to attach at a higher position in the matrix clause structure. However, examples like (28) do not pose a challenge because they instantiate cases of what has been referred to as modal subordination. Roberts (1987;1989: 718) defines modal subordination as a "phenomenon wherein the interpretation of a clause α is taken to involve a modal operator whose force is relativized to some set β of contextually given propositions." What this boils down to is that variable binding does not apply as a diagnostic test determining the status of chyba-że-clauses.
What we have seen so far is that in comparison to negated jeśli-conditionals, chyba-że-clauses appear 'deficient'. Table 1 summarizes the main findings.
These differences strongly indicate that exceptive chyba-że-clauses cannot be treated as negated conditionals. The next section shows that chyba-że-clauses are peripheral adverbial clauses, and that they have the internal structure of root clauses equipped with ForceP.

Exceptive chyba-że-clauses as JudgeP modifiers
In this section, I discuss the external and internal syntax of chyba-że-clauses.

External syntax
As observed in the previous subsection, chyba-że-clauses are not sensitive to elements occurring in the matrix clause. This led us to the conclusion that they are not strongly integrated into the host clause. If this is the case, chyba-że-clauses are expected not to fall in the scope of a matrix property exceptive clauses negated conditionals left periphery -+ non-assertive speech acts: questions -+ focus particle tylko 'only' -+ emotive predicates -+ factual conditionals -+ To account for this contrast, Anand & Hacquard (2013) divide attitudes, following Bolinger (1968), into two classes: i) representational and ii) non-representational, whereby only the former do quantify over an information state, e.g., a set of beliefs for believe, which epistemic modal verbs can be anaphoric to. Non-representational attitudes, in turn, are taken not to quantify over an information state. In this spirit, Anand & Hacquard (2013) propose Epistemic Licensing Generalization: (34) (Lund & Charnavel 2020: 166, ex. 21a-b) a. John thinks that Paul went for a walk even though it's raining (but it's not actually raining). b. John wishes that Paul would go for a walk even though it's raining (*but it's not actually raining).
The contrast between (34a) and (34b) shows that even though-clauses pattern with epistemic modal verbs. If they were embedded, the inference that the subordinate clause holds would be cancellable. This is clearly not the case. Czyba-że-clauses behave similarly. They can be embedded under representational attitude predicates (e.g. myśleć 'think'), but not under nonrepresentational ones (e.g. pragnąć 'desire'): (35) a. Jacek myśli, że dzisiaj po południu mogą wyjść na wolność, Jacek think.3sg that today after midday.loc can.3pl go:out.inf on freedom.acc chyba że sąd zdecyduje inaczej (ale tak naprawdę to sąd nie unless court decide.3sg differently but so really then court neg zdecyduje inaczej). decide.3.sg differently 'Jacek thinks that they are allowed to be released from the prison today afternoon, unless the court will take a different decision (but in fact the court won't take a different decision).' b. Jacek życzy sobie, żeby dzisiaj po południu wyszli na Jacek wish.3sg refl that today after midday.loc go:out.l-ptcp.vir on wolność, chyba że sąd zdecyduje inaczej (*ale tak naprawdę to freedom.acc unless court decide.3sg differently but so really then sąd nie zdecyduje inaczej). court neg decide.3.sg differently 'Jacek wishes that they would be allowed to be released from the prison today afternoon, unless the court will take a different decision (*but in fact the court won't take a different decision).' Lund & Charnavel (2020) assume that even though-clauses attach as EpisP modifiers, i.e., they adjoin to a higher functional projection, to Mod epistemic in Cinque's (1999)  Now, I examine the internal syntax of chyba-że-clauses and argue that they project up to ForceP, as suggested in (37).

Internal syntax
Having determined the attachment height of chyba-że-clauses, I now turn to their internal syntax.
Epistemic and evidential adverbs expressing speaker's attitude towards what is embedded are usually taken to be base-generated within the C-domain (cf. Cinque 1999). The discourse particle chyba 'presumably' itself can be classified as an epistemic expression. Using chyba, the speaker indicates that her / his commitment towards the truth of what is embedded is speculative. Accordingly, it contributes to a weaker commitment of the speaker to the proposition. Now, if exceptive chyba-że-clauses are not integrated into the host clause, they are supposed to be able to host discourse particles. This is, however, not the case, as (38) shows: Dzisiaj po południu mogą wyjść na wolność, chyba że (*chyba) today after midday.loc can.3pl go:out.inf on freedom.acc unless presumably sąd (*chyba) zdecyduje (*chyba) inaczej. court presumably decide.3sg presumably differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless (presumably) the court (presumably) will take (presumably) a different decision.' The impossibility of using chyba 'presumably' in exceptive clauses headed by chyba że is mainly due to the fact that the original meaning of the homophonous preposition chyba 'except' has not been completely bleached when it was recruited for the exceptive clause structure. But if we take chyba-że-clauses to be peripheral adverbial clauses, we also expect them to be able to host other speaker-oriented adverbs. This prediction is borne out: Dzisiaj po południu mogą wyjść na wolność, chyba że sąd today after midday.loc can.3pl go:out.inf on freedom.acc unless court może / prawdopodobnie / rzekomo zdecyduje inaczej. maybe / probably / supposedly decide.3sg differently 'They are allowed to be released from the prison today afternoon, unless the court maybe / probably / supposedly will take a different decision.' In (39), we can find the epistemic adverbs może 'maybe' and prawdopodobnie 'probably' and the evidential adverb rzekomo 'supposedly'. In the approach taken by Krifka (to appear) such expressions are analyzed as judgement modifiers base-generated in the functional projection JudgeP placed above TP. Accordingly, chyba-że-clauses are at least JudgePs. In the analysis proposed by Frey (to appear[a]) JudgeP modifiers are weak root phenomena. To fully examine the internal structure of chyba-że-clauses, we need strong root phenomena, i.e. speech act modifiers c-commanding judgement modifiers. A sample of speech act modifiers is given in (40) It straightforwardly follows that chyba-że-clauses are subordinate clauses being capable of hosting speech act modifiers, leading to the conclusion that their internal structure is like the one of root clauses, i.e. equipped with ForceP or ActP in Krifka's terminology.

Exceptive clauses in the history Polish
The main aim of this section is to describe the use of chyba in historical stages of Polish. Based on Klemensiewicz (2009), Walczak (1999, and Dziubalska-Koaczyk & Walczak (2010), I distinguish four language stages in the history of Polish as given in Table 2

Etymology
Etymologically, the discourse particle chyba 'presumably' must have emerged out of the verb chybić 'to miss' / 'to mistake' / 'to lack' which is still present in PdP: (42) Chybiłeś. miss.l-ptcp.2sg 'You missed.' They can even co-occur which is mainly due to the fact that the verb chybić narrowed down its lexical meaning and cannot mean 'to lack' in PdP: (43) Chyba chybiłeś. chyba miss.l-ptcp.2sg 'Presumably, you missed.' Furthermore, chyba could also be used as a preposition selecting noun phrases marked for the Genitive case: 9 (44) (Andrzej Glaber, 1535;cit. in Brückner 1927: 188) wszelkie zwierzę chyba człowieka uszami rusza every animal chyba man.gen ears.ins move.3sg 'every animal except man moves his ears' In (44) chyba has a narrow scope and selects the noun człowieka 'man'. Its meaning can be paraphrased as 'except', 'excluding'. Brückner (1927: 188) mentions the use of chyba as a noun 'lack of' which is supposed to have disappeared in the 16th century, and paved the way for the prepositional use. Remarkably, the use of chyba as a preposition disappeared from language use.
In PdP poza selecting noun phrases marked for the Instrumental case is used instead of chyba: (45) a. *chyba człowieka except man.gen Intended: 'except for man' b. poza człowiekiem except man.ins 'except for man' In Section 4, I show that the use of chyba as a preposition was crucial for the development of exceptive clauses.

Old Polish (until 1543)
In

Middle Polish (1543-1765)
To begin with, I discuss mp data from the PolDi corpus. In principle, in mp exceptive structures the conditional clitic by occurs adjacent to the complementizer że: In Listy do Marysieńki (1665-1683) ('Letters to Marysieńka') chyba is attested in 39 contexts. Table 3 shows its distribution. Chyba occurs as a discourse particle, a preposition and in combination with że 'that' as an adverbial complementizer.
The data extracted from PolDi resemble the use of chyba in another corpus. In general, I extracted 46 cases from the KorBa corpus, also known as The Baroque Corpus of Polish. 12 An overview of how chyba was used in mp is given in Table 4.
Firstly, what appears to be interesting is the fact that chyba can occur with other complementizers giving rise to an exceptive interpretation. In (54) the preposition chyba 'except' combines with the conditional / temporal complementizer gdy 'if' / 'when' and with the conditional clitic by.
Taken together they render the meaning of the English complementizer unless: 12 KorBa contains historical texts from the 17th and 18th centuries, consists of 718 texts, counts over 10 million word forms, and is available for free. discourse particle chyba że + verb chyba żeby + verb preposition 21 (47%) 4 (7%) 1 (2%) 20 (44%) (54) (KorBa, Jeremian Niewieściński, Prerogatywa abo wolność mężatkom, 1684-1700) Bo się takich plotek mężom swym nie zwykły because refl such rumors husbands.dat their neg use.l-ptcp.pl.n-vir małżonki sprawować, chyba gdy-by jeszcze młode i głupie były. wives behave.inf chyba if/when-cond still young and stupid be.l-ptcp.pl.n-vir 'Because wives usually don't behave to their husbands this way, unless they are still young and stupid.' Other complementizers can be attested, as well: (55) (Łókasz Górnicki, Dworzanin polski, 1566, Aa5: 8) chybá ieſli mu ſie cżáſem z okná widzieć dáłá chyba if him.dat refl sometimes from window see.inf give.l-ptcp.sg.fem 'unless she allowed him to see her from the window sometimes' Instead of the complementizer że 'that', a wh-phrase can follow chyba: (56) (Łókasz Górnicki, Dworzanin polski, 1566, E2: 11-13) Wſzákoż nie-chcę / áby do tákowey poiedynkiem bitwy był chćiwy but neg-want.1sg / that to such duel battle be.l-ptcp.sg.m greedy / chybá gdzie-by mu ſzło o pocżćiwość. / chyba where-cond him.dat go.l-ptcp.sg.n about kind-heartedness 'But I don't want him to fight, unless the issue concerns kind-heartedness.' Note that such constellations are not possible in PdP, neither with indicative morphology nor with conditional morphology: (57) *Dzisiaj po południu mogą wyjść na wolność, chyba gdy(-by) / today afternoon may.3pl go:out.inf on freedom chyba if / when-cond / jeśli(-by) / gdzie(-by) sąd zdecyduje / zdecydował inaczej. if-cond / where-cond court decide.3sg / decide.l-ptcp.sg.m differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' This contrast reveals one considerable issue: In mp -as well as in op -the exceptive meaning does not come about the inherent complementizer chyba że 'unless', as is the case in contemporary Polish. Rather, it is due to the compositional meaning of the preposition chyba 'except' and the following complementizer that in older stages of Polish was not restricted to the declarative complementizer że 'that.' Secondly, chyba as a preposition can combine with the conditional clitic by and have both a narrow and a wider (= propositional) scope: (58) (KorBa, Rozmowa dwóch szlachty, 1733) ale z nim na plac jeszcze nie wyjeżdżają, ten cale u dam polskich but with him on square yet neg go:out.3pl this altogether at ladies Polish nie ma estymacji, [chyba-by [ PP u starych]] neg have.3sg estimation.gen chyba-cond at old 'they don't go with him to the square yet, he is not appreciated by Polish ladies, except for the old ones' (59) (KorBa, Wojciech Laktański, Czarownica powołana, 1680) Piąta ma być powołanie abo pomowa / nie tak od tego który fifth have.3sg be.inf call or opinion / neg so from this:one who skarży na niego / ale od drugich ludzi wiary godnych; [chyba-by accuse.3sg on him / but from other people belief.gen worthy chyba-cond [ PartP były insze jasne dokumenta]] / na ten czas tej pomowy nie trzeba. be.l-ptcp.pl.n-vir other clear documents / on this time this opinion neg need.3sg 'Fifth, it needs to be a call or an opinion, not from the person who is accusing but from reliable people; unless there would be other documents, in this case an opinion is not needed.' In both cases, chybaby should be analyzed as a preposition meaning 'except (for)'. In (58), it combines with the PP u starych 'by old (people)'. In (59), chybaby embeds a participial complement. Remarkably, in PdP chybaby can only have a propositional scope; it cannot scope over smaller constituents: (60) *Nie chodzę na imprezy, chyba-by do Anny. neg go.1sg on parties chyba-cond to Anna Intended meaning: 'I don't go to parties, except for Anna's parties.' And even if it takes a propositional scope, it does not mean 'unless': Nie chodzę na imprezy, chyba-by-m oszalał. neg go.1sg on parties chyba-cond-1sg get:crazy.l-ptcp.sg.m 'I don't go to parties, I'd get crazy.' Intended meaning: *'I don't go to parties, unless I'd get crazy.' In other words, the example given in (1) cannot be used in connection with chybaby: (62) *Dzisiaj po południu mogą wyjść na wolność, chyba-by sąd zdecyduje / today afternoon may.3pl go:out.inf on freedom chyba-cond court decide.3sg / zdecydował inaczej. decide.l-ptcp.sg.m differently Intended meaning: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' Based on these differences it is tempting to examine data from np to see how chyba-że-clauses developed.

New Polish (1765-1939)
I extracted and analyzed 177 chyba-cases from NewCor, a Corpus of  Polish.
The use of chyba as a discourse particle is strongly preferred:

Interim conclusion
We can recapitulate our diachronic findings as presented in Table 5  What we can conclude from our diachronic findings is that exceptionality was expressed almost in all historical stages of Polish by means of the preposition chyba and the following complementizer which, in turn, could be a declarative complementizer, a conditional subjunction or a wh-phrase. I refer to these structures as exceptive structure in Table 5 Diachronically, we can safely assume that (68b) occurred as first in the history of Polish. Then, indicative mood started to be preferred in the exceptive clause, (68a), whereas at the same time (68c) could be used, as well. As the next section shows, it is not surprising that the conditional clitic by contributed to the origin of the inherent exceptive complementizer chyba że 'unless'.

Reanalysis
Typologically, not much is known about how exceptive clauses come into being. Traugott Based on the data discussed in Section 3, I propose the following development steps of exceptive clauses in Polish.
PP NP N 0 człowieka P 0 chyba Semantically, chyba introduces an exception and triggers a set of alternatives. By excluding the human being, the speaker assumes the existence of other species moving their ears. In other words, chyba employed as a preposition fulfills already two functions important for the development of exceptive clauses. But to operate on the clausal level, its scope needs to be extended. This is achieved by the use of correlative elements referring to the content of the relative clause modifying these elements: (70) a. (Brückner 1927: 188) (70a), chyba is still used as a preposition and its embeds the demonstrative pronoun tego 'this' marked for the Genitive case. The demonstrative, in turn, is co-indexed with the following iż-clause (for further developments of iż across Slavic languages, see Meyer 2017). The conditional morphology on the complementizer triggers counterfactuality, i.e. the existence of a set of alternatives (Stalnaker 1968;Lewis 1973;von Fintel 2011). What chyba does in this connection is that it picks out the most prominent proposition from the set of alternatives referring to the correlative element tego 'this'.
Step 2: Chyba does not change its status; it still functions as a preposition, but in addition to NP/DP complements, it can also take CP complements. What is important to keep in mind, though, is that chyba and the complementizer / wh-phrase introducing the subordinate clause do not form a single constituent. Instead, they are to be analyzed as two separate forms:  (72a), ii) by the wh-phrase wo 'where' in (72b), and iii) by the declarative complementizer dass 'that' in (72c). But contrary to the history of Polish, none of these elements grammaticalized with the preposition außer 'except' into a morphologically complex C-head. This is mainly due to the fact that German developed another exceptive connective, es sei denn 'unless', having also the possibility to scope over CPs (for more diachronic details on es sei denn, see Witzenhausen 2019).
Step 3: From late Middle Polish onwards, chyba and że occur without conditional morphology: (73) (PolDi, Listy do Marysi, 1668) poczta francuska do Warszawy chodzić przestanie, chyba że sami kupcy (…) post French to Warsaw go.inf cease.3sg chyba that alone sellers (…) wynajdą jaki między sobą sposób find:out.3pl some among refl way 'the French post to Warsaw will not be offered, unless sellers themselves (…) find another way among themselves' I assume (73) to be one of the first cases in which the combination of chyba and że is allowed to be analyzed as a complex C-head, i.e., as an indivisible lexical unit, (74b). In other words, due to head adjunction both functional elements grammaticalized into a single functional head, as Diachronically, it is not surprising that a preposition becomes a C-head or a part of it; compare, for example, German bis 'until' introducing finite temporal clauses or um (lit. 'around') 'in order to' selecting non-finite purpose clauses (Jędrzejowski 2021) or English for, till, like (van Gelderen 2004: 101-7, 124-5). Blümel & Pitsch (2019: 3-4) give a rich overview of adverbial complementizers containing a preposition in selected Slavic languages. I argue that chyba as a preposition lost its prepositional case feature. If chyba were still a preposition, it would be a case assigner, which is obviously not the case: (75) *Dzisiaj po południu mogą wyjść na wolność, chyba że sądu today after midday.loc can.3pl go:out.inf on freedom.acc unless court.gen zdecyduje inaczej. decide.3sg differently Intended: 'They are allowed to be released from the prison today afternoon, unless the court will take a different decision.' Following van Gelderen (2010), I assume chyba as a preposition to have lost its [gen]-feature, paving the way for the incorporation into the C-domain and for the adjunction to the declarative complementizer że 'that': (76) P 0 [u-phi, gen, i-exception] -> C 0 [u-phi, i-exception] Importantly, it did not loss its all features though. It keeps the interpretable feature [+exception], and changes its uninterpretable feature associated with selectional requirements (cf. P-heads taking DPs as their complements vs. C-heads taking TPs; see also Roussou 2020).
Furthermore, the following steps deserve to be accounted for. Prior to the mp period exceptive structures must have required the preposition chyba 'except' selecting a CP complement. The conditional clitic by climbed up in the structure to join the complementizer. Taken together they compositionally gave rise to exceptive meaning which has been accommodated over time.
First instances of this change are to be observed from Middle Polish onwards, as (73) clearly illustrates. Of course, it does not mean that the original structure with the conditional clitic by automatically disappeared. Quite the contrary, it co-exists next to the structure with the inherent complementizer chyba że 'unless'. But once the accommodation has taken place, the movement of the clitic by is not needed any longer. It can remain in-situ and attracts an l-participle. This scenario reminds of a cycle in the sense advocated by van Gelderen (2009, 2011:3), whereby "toward the end of the cycle, similar events start again, but they are (slightly) different and happen at a difference pace". What the conditional clitic by does is the same in both patterns: It introduces a set of alternatives. But whereas in older stages of Polish it goes up to the C-head to pave the way for the origin of the exceptive complementizer, in PdP it introduces a set of alternatives in relation to the exceptive clause. In this case, it is not required to move as high as the C-head is base-generated. This scenario has also another conceptual advantage. No radical reanalysis of the sentence boundary needs to be postulated as both chyba and że were constituents of the second clause before and after the reanaylsis. They did not change their positions on the surface. Only the status of chyba changed from that of a preposition to part of a complementizer.
Main evidence for this view comes from two observations made at the beginning of the present article, viz. that że in chyba że cannot be replaced by any other complementizer and that chyba cannot be dropped.
Step 4: The status of the complex single complementizer makes the conditional morphology redundant. Conditional morphology introduces a silent set of alternatives, and so does the exceptive complementizer chyba że. As Vostrikova (2018) convincingly shows, the set of alternatives for a proposition denoted by an exceptive clause and by a negated conditional clause that are negated by an exhaustifier is constructed in the same way. In this sense, the grammaticalized complementizer chyba że prevails, as it incorporates the set of alternatives in its lexical meaning, whereas conditional morphology presupposes such a set. When the set of alternatives is lexically stored, there is no need to introduce it additionally in terms of a presupposition. Accordingly, from the 19th century onwards, the indicative mood is favored in exceptive clauses: Exceptive structures containing the preposition chyba 'except' and other complementizers than że disappear (but see Footnote 3 above). The preposition chyba 'except' itself disappears from language use. Its meaning is covered by the preposition poza 'except' and by lexical expressions like z wyjątkiem 'with the exception of'. The presence of ForceP indicates the possibility of using speech act modifiers, as exemplified in (41a)-(41c). As exceptive chyba-że-clauses project up to ForceP, they are also expected to host epistemic and evidential expressions, i.e., judge modifiers in Krifka's (to appear) terms. This prediction could be borne out based on examples like the one in (39) discussed in Section 2.3.

Conclusion
This article was concerned with the synchrony and diachrony of exceptive clauses in Polish introduced by the morphologically complex complementizer chyba że 'unless'. Chyba-że-clauses are analyzed as JudgeP adjuncts that depend on the illocutionary force of the entire utterance and that differ from negated conditionals at the syntax-semantics interface in many respects.
Diachronically, I argued that the origin of chyba że was possible due to several syntactic and semantics factors: i) strict structural adjacency of the preposition chyba 'except' and the declarative complementizer że 'that' , ii) movement of the conditional clitic by to the C-domain giving rise to a counterfactual interpretation and triggering a set of alternative worlds, and, finally, iii) scope as well as the truth conditions of the preposition itself. The diachronic data discussed in the present article indicated that the compositional meaning of the conditional clitic and of the preposition were accommodated into the meaning of the exceptive complementizer in the Middle Polish period (1543-1765). Against this background it is therefore tempting to examine the diachrony of exceptive clauses cross-linguistically, as fine-grained analyses depicting individual micro-steps of how exceptive clauses come into being and develop may shed new light on how exceptives behave synchronically.