[This post is part of a series on theories of lexical exceptionality.]
I now take a large jump in exceptionality theory from the late ’70s to the mid-aughts. (I am skipping over a characteristically ’90s approach, which I’ll cover in my final post.) I will focus on a particular approach—not the only one, but arguably the most robust one—to exceptionality in Optimality Theory (OT). This proposal is as old as OT itself, but is developed most clearly in Pater (2006), and Pater & Coetzee (2005) propose how it might be learned. I will also briefly discuss the application of the morpheme-specific approach to the yer patterns characteristic of Slavic languages by Gouskova and Rysling, and Rubach’s critique of this approach.
I will have very little to say about the cophonology approach to exceptionality that has also been sporadically entertained in OT. Cophonology holds that morphemes may have arbitrarily different constraint rankings. Pater (henceforth P) is quite critical of this approach throughout his 2006 paper: among other criticisms, he regards it as completely unconstrained. I agree: it makes few novel predictions, and would challenge cophonologists (if any exist in 2024) to consider how cophonology might be constrained so as to derive interesting predictions about exceptionality.
Indexed constraints
Even the earliest work in Optimality Theory supposed that some constraints might be specific to particularly grammatical categories or morphemes. This of course is a loosening of the idea that Con, the universal constraint family, is language-universal and finite, but it seems to be a necessary assumption. P claims that this device is powerful enough to handle all known instances of exceptionality in phonology. The basic idea is extremely simple: for every constraint X there may also exist indexed constraints of the form X(i) whose violations are only recorded when the violation occurs in the context of some morpheme i.1 There are then two general schemas that produce interesting results.
(1) M(i) >> F >> M
(2) F(i) >> M >> F
Here M stands for markedness and F for faithfulness. As will be seen below, (1) has a close connection to the notions of mutability and catalysis introduced in my earlier post; (2) in turn has a close connection with quiescence and inalterability.
One of P’s goals is to demonstrate that this approach can be applied to Piro syncope. His proposal is not quite as detailed as one might wish, but it is still worth discussing and trying to fill in the gaps. For P, the general syncope pattern arises from the ranking Align-Suf-C >> Max; in prose, it is permissible to delete a segment if doing so brings the suffix in contact with a consonant. This also naturally derives the non-derived environment condition since it specifically mentions suffixhood. P derives the avoidance of tautomorphemic clusters, previously expressed with the VC_CV environment, with the markedness constraint *CCC. This gives us *CCC >> Align-Suf-C >> Max thus far. This should suffice for derivations whose roots are all mutable and catalytic.
For P, inalterable roots are distinguished from mutable ones by an undominated, indexed clone of Max which I’ll call Max(inalt), giving us a partial ranking like so.
(3) Max(inalt) >> Align-Suf-C >> Max
This is of course an instance of schema (2). Note that since the ranking without the indexing is just Align-Suf-C >> Max, it seemingly treats mutability as the default and inalterability as exceptional, a point I’ll return to shortly.
Quiescent roots in P’s analysis are distinguished from catalytic ones by a lexically specific clone of Align-Suf-C; here the lexically indexed one targets the catalytic suffixes, so we’ll write it Align-Suf-C(cat), giving us the following partial ranking.
(4) Align-Suf-C(cat) >> Max >> Align-Suf-C
This is an instance of schema (1). It is interesting to note that the Align constraint bridges the distinction between target and trigger, since the markedness is a property of the boundary itself. Note also that it also seems to treat quiescence as the default and catalysis as exceptional.
Putting this together we obtain the full ranking below.
(5) *CCC, Max(inalt) >> Align-Suf-C(cat) >> Max >> Align-Suf-C
P, unfortunately, does not take the time to compare his analysis to Kisseberth’s (1970) proposal, or to contrast it with Zonneveld’s (1978) critiques, which I discussed in detail in the earlier post. I do observe one potential improvement over Kisseberth. Recall that Kisseberth had trouble with the example /w-čokoruha-ha-nu-lu/ [wčokoruhahanru] ‘let’s harpoon it’ , because /-ha/ is quiescent and having a quiescent suffix in the left environment is predicted counterfactually to block deletion in /-nu/. As far as I can tell this is not a problem for P; the following suffix /-lu/ is on the Align-Suf-C(cat) lexical list and /-nu/ is not on the Max(inalt) list and that’s all that matters. Presumably, P gets this effect because of the joint operation of the two flavors of Align-Suf-C and *CCC means has properly localized the catalysis/quiescence component of the exceptionality. However, P’s analysis does not seem to generate the right-to-left application; it has no reason to favor the attested /n-xipa-lu-ne/ [nxipalne] ‘my sweet potato’ over *[nxiplune]. This reflects a general issue in OT in accounting for directional application.
As I mentioned above, P’s analysis of Piro treats mutability and quiescence as productive and inalterability and catalysis as exceptional. Indeed, it predicts mutability and quiescence in the absence of any indexing, and one might hypothesize that Piro speakers would treat a new suffix of the appropriate shape as mutable and quiescent. I know of no reason to suppose this is correct; for Matteson (1965), these are arbitrary and there is no obvious default, whereas my impression is that Kisseberth views mutability (like P) and catalysis (unlike P) as the default. This question of productivity is one that I’ll return to below as I consider how indexing might be learned.
Learning indexed constraints
Pater and Coetzee (2005, henceforth P&C) propose indexed constraint rankings can be learned using a variant of the Biased Constraint Demotion (BCD) algorithm developed earlier by Prince and Tesar (2004). Most of the details of that algorithm are not strictly relevant here; I will focus on the ones that are. BCD supposes that learners are able to accumulate UR/SR pairs and then use the current state of their constraint hierarchy to record them as a data structure called a called mark-data pair. These give, for each constraint violation, whether that violation prefers the actual SR or a non-optimal candidate. From a collection of these pairs it is possible to rank constraints via iterative demotion.2 The presence of lexical exceptionality produces a case where it is not possible to for vanilla BCD to advance the demotion because a conflict exists: some morphemes favor one ranking whereas others favor another. P&C propose that in this scenario, indexed constraints will be introduced to resolve the conflict.
P&C are less than formal in specifying how this cloning process works, so let us consider how it might function. Their example, a toy, concerns syllable shape. They suppose that they are dealing with a language in which /CVC/ is marked (via NoCoda) but there are a few words of this shape which surface faithfully (via Max). They suppose that this results in a ranking paradox which cannot be resolved with the existing constraints. As stated, I have to disagree: their toy provides no motivation for NoCoda >> Max.3 Let us suppose, though, for sake of argument that there is some positive evidence, after all, for that ranking. Perhaps we have the following.
(6) Toy grammar (after P&C):
a. /kap/ – > [ka]
b. /gub/ -> [gu]
c. /net/ -> [net]
d. /mat/ -> [mat]
Let us also suppose that there is some positive evidence that /kap, gub/ are the correct URs so they are not changed to faithful URs via Lexicon Optimization. Then, (6ab) favor NoCoda >> Max but (6cd) favor Max >> NoCoda. P&C suppose this is resolved by cloning (i.e., generating an indexed variant of) Max, producing a variant for each faithfully-surfacing /CVC/ morpheme. If these morphemes are /net/ and /mat/, then we obtain the following partial ranking after BCD.
(7) Max(net), Max(mat) >> NoCoda >> Max
This is another instance of schema (2); there are just multiple indexed constraints in the highest stratum. Indeed, P&C imagine various mechanisms by which Max(net) and Max(mat) might be collapsed or conflated at a later stage of learning.
It is crucial to the P&C’s proposal that the child actual observes the exceptional morphemes both of (6cd) surfacing faithfully; however, it is not necessary to observe (6ab), just to observe some morphemes in which, like in (6ab), a coda consonant is deleted so as to trigger cloning. The critical sample for (7), then, is either (6acd) or (6bcd). It is not necessary to see both (6a) and (6b), but it is necessary to see both of (6cd). Thus, there is some very real sense in which this analysis treats coda deletion as the productive default and coda retention as exceptional behavior, much like how P’s analysis of Piro treated mutability and quiescence as productive. However, it seems like P&C could have instead adapted schema (1) and proposed that what is cloned is NoCoda, obtaining the following ranking.
(8) NoCoda(kap), NoCoda(gub) >> Max >> NoCoda
Then, for this analysis, the crucial sample is either (6abc) or (6abd), and there is a similar sense in which coda retention is now the default behavior.
P&C give no reason to prefer (7) over (8). Reading between the lines, I suspect they imagine that the relative frequency (i.e., number of morpheme types) which either retain or lose their coda is the crucial issue, and perhaps they would appeal to an informal “majority-rules” principle. That is, if forms like (6ab) are more frequent than those like (6cd) they would probably prefer (7) and would prefer (8) if the opposite is true. However, I think P&C should have taken up this question and explained what is cloned when. Indeed, there is an alternative possibility: perhaps cloning produces all of the following constraints in addition to Max and NoCoda.
(9) Max(kap), Max(gub), Max(net), Max(mat), NoCoda(kap), NoCoda(gub), NoCoda(net), NoCoda(mat)
While I am not sure, I think BCD would be able to proceed and would either converge on (7) or (8), depending on how it resolves apparent “ties”.
Another related issue, which also may lead to the proliferation of indexed constraints, is that P&C have little to say about how constraint cloning words in complex words. Perhaps the cloning module is able to localize the violation to particular morphemes. For instance, it seems plausible that one could inspect a Max violation, like the ones produced by Piro syncope, to determine which morpheme is unfaithful and thus mutable. However, if we wish to preserve P’s treatment of mutability as the default (and that inalterable morphemes have a high-ranked Max clone), we instead need to do something more complex: we need to determine that a certain morpheme does not violate Max (good so far), but also that under a counterfactual ranking of this constraint and its “antagonist” Align-Suf-C, would have done so; this may be something which can be read off of mark-data pairs, but I am not sure. Similarly, to preserve P’s treatment of quiescence as the default, we need to determine that a certain suffix has an Align-Suf-C violation (again, good so far), but also that under a counterfactual ranking of this constraint and its antagonist, it would have not done so.
While I am unsure if this counterfactual reasoning part of the equation can be done in general, I can think of least one case where the localization reasoning cannot be done: epenthesis at morpheme boundaries, as in the [-əd] allomorph of the English regular past. Here there is no sense in which the Dep violation can be identified to a particular morpheme. Indeed, Dep violations are defined by the absence of correspondence. This is a perhaps an unfortunate example for P&C’s approach. English has a number of few “semiweak” past tense forms (e.g. from Myers 1987: bit, bled, hid, met, sped, led, read, fed, lit, slid) which are characterized by a final dental consonant and shortening of the long nucleus of the present tense form. Given related pairs like keep-kept, one might suppose that these bear a regular /-d/ suffix, but fail to trigger epenthesis (thus *[baɪtəd], etc.). To make this work, we assume the following.
(10) Properties of semiweak pasts:
a. Verbs with semiweak pasts are exceptionally indexed to a high-ranking Dep constraint which dominates relevant syllable structure markedness constraints.
b. Verbs with semiweak pasts are exceptionally indexed to high-ranking markedness constraint(s) triggering “Shortening” (in the sense of Myers 1987)
c. A general (i.e., non-indexed) markedness constraint against hetero-voiced obstruent clusters dominates antagonistic voice faithfulness constraints.
The issue is this: how do children localize the failure of epenthesis in (10a) to the root and not the suffix, given that the counterfactual epenthetic segment is not an exponent of either, occurring rather at the boundary between the two? Should one reject the sketchy analysis given in (10), there are surely many other cases where correspondence alone is insufficient; for example, consider vowels which coalesce in hiatus.
The yers
I have again already gone on quite long, but before I stop I should briefly discuss the famous Slavic yers as they relate to this theory.
In a very interesting paper, Gouskova (2012) presents an analysis of the yers in modern Russian. In Russian, certain instances of the vowels e and o alternate with zero in certain contexts. These alternating vowels are termed yers in traditional Slavic grammar. A tradition, going back to early work by Lightner (1965), treats yers in Russian and other Slavic languages, as underlyingly distinct from non-alternating e and o, either featurally or, in later work, prosodically. For example, лев [lʲev] ‘lion’ has a genitive singular (gen.sg.) льва [lʲva] and мох [mox] ‘moss’ has a gen.sg. [mxa].
Gouskova (henceforth G) wishes to argue that yer patterns are better analyzed using indexed constraints, thus treating morphemes with yer alternations as exceptional rather than treating the yer segments as underspecified. In terms of the constraint indexing technology, G’s analysis is straightforward. Alternating vowels are underlyingly present in all cases, and their deletion is triggered by a high-ranked constraint *Mid (which disfavors mid vowels, naturally) which is indexed to target exactly those morphemes which contain yers. Additional phonotactic constraints relating to consonant sequences are used to prevent deletion that produces word-final consonant clusters. Roughly, then, the analysis is:
(11) *CC]σ >> *Mid(yer morphemes) >> Max-V >> *Mid
As G writes (99-100, fn. 18): “In Russian, deletion is the exception rather than the rule: most morphemes do not have deletion, and neither do loanwords…”
It should be noted that G’s analysis departs from the traditional (“Lightnerian”) analysis in ways not directly to the question of localizing exceptionality (i.e., in the morpheme vs. the segment). For one, (11) seems to frame retention of a mid vowel as a default. In contrast, the traditional analysis does not seem to have any opinion on the matter. In that analysis, whether or not a mid vowel is alternating is a property of its underlying form, and should thus be arbitrary in the Saussurean sense. This is not to say that we expect to find yers in arbitrary contexts. There are historical reasons why yers are mostly found in the final syllable—this is the one of the few places where the historical sound change called Havlík’s Law, operating more or less blindly, could introduce synchronic yer/zero alternations in the first place (in many other contexts the yers were simply lost), and in other positions it is impossible to ascertain whether or not a mid vowel is a yer. Whether or not an alternative versions of the sound change could have produced an alternative-universe Russian where yers target the first syllable is an unknowable counterfactual given that we live in our universe, with our universe’s version of Havlík’s Law. Secondly, the traditional analysis (see Bailyn & Nevins 2008 for a recent exemplar) usually conditions the retention of yers on the presence of a yer (which may or may not be itself retained) in the following syllable. In contrast, G does not seem to posit yers for this purpose nor does she condition their retention on the presence of nearby yers. In the traditional analysis, these conditioning yers are motivated by the behavior of yers in prefixes and suffixes in derivational morphology, and much of this hinges on apparent cyclicity. G provides an appendix in which she attempts to handle several of these issues in her theory, but it remains to be seen whether this has been successful in dismissing all the concerns one might raise.
G provides a few arguments as to why the exceptional morpheme analysis is superior to the traditional analysis. G wishes to establish that mid vowels are in fact marked in Russian, so that yer deletion can take a something of a “free ride” on this constraint. As such, she claims that yer deletion is related to the reduction of mid vowels in unstressed syllables. But how do we know that these these facts are connected? And, if they are in fact connected, is it possible that there is an extra-grammatical explanation? For instance, there may be a “channel bias” in production and/or perception that disfavors faithful realization of mid vowels (and thus imposes a systematic bias in favor of reduction and deletion) compared to the more extreme phonemic vowels (in her analysis, /a, i, u/) which caused the actuation of both changes. Phenomenologically speaking, it is true that there are two ways in which certain Russian mid vowels are unfaithful, but this is just one of a infinite set of true statements about Russian phonology, and there is something “just so” about this one.
Before I conclude, let us now turn briefly to Polish. Like Russian, this language has mid-vowels which alternate with zero in certain contexts. (Unlike Russian, for whatever reason, the vast majority of alternating vowels are e; there are just three morphemes which have an alternating o.)
Rubach (2013, 2016), explicitly critiques constraint indexation using data from Polish. Rubach argues that G’s analysis cannot be generalized straightforwardly to Russian. He draws attention to stems that contain multiple mid vowels, only one of which is a yer (e.g., sfeter/sfetri ‘sweater’); and concludes that it is not necessarily possible to determine which (or both) should undergo deletion in an “exceptional” morpheme. The only mechanism with which one might handle this is a rather complex series of markedness constraints on consonant sequences. Unfortunately, Polish is quite permissive of complex consonant clusters and this mechanism cannot always be relied upon to deliver the correct answer. He also draws attention to the behavior of derivational morphology such as double diminuitives. In contrast, Rysling (2016) attempts to generalize G’s indexed constraint analysis of yers to Polish. However, her analysis differs from G’s analysis of Russian in that she derives the yers from epenthesis to avoid word-final consonant clusters. Furthermore, for Rysling, epenthesis, in the relevant phonotactic contexts (to a first approximation, certain C_C#), is the default, and failure to epenthesize is exceptional.5 Sadly, there is little interaction between the Rubach and Rysling papers (the latter briefly discusses the former’s 2013 paper), so I am not prepared to say whether Rysling’s radical revision addresses Rubach’s concerns with constraint indexation.
References
- P and colleagues refer to these constraints as “lexically specific”, but in fact it seems the relevant structures are all morphemes, and never involve polymorphemic words or lexemes.
- As far as I know, though, there is no proof of convergence, under any circumstances, for BCD.
- Perhaps they are deriving this from the assumption that the initial state is M >> F, but without alternation evidence, BCD would rerank this as Max >> NoCoda and cloning would not be triggered.
- A subsequent rule of obstruent voice assimilation, which is needed independently would give us [kɛpt] from /kip-d/, and so on.
- Rysling seems to derive this proposal from an analysis of lexical statistics: she counts how many Polish nouns have yer alternations in the context …C_C# and compares this to non-alternating …CeC# and …CC#. It isn’t clear to me how the proposal follows from the statistics, though: non-epenthesis and epenthesis in …C_C# are about equally common in Polish, and their relative frequencies are not much different from what she finds in Russian.
References
Bailyn, J. F. and Nevins, A. 2008. Russian genitive plurals are impostors. In A. Bachrach and A. Nevins (ed.), Inflectional Identity, pages 237-270. Oxford University Press.
Gouskova, Maria. 2012. Unexceptional segments. Natural Language & Linguistic Theory 30: 79-133.
Kenstowicz, M. 1970. Lithuanian third person future. In J. R. Sadock and A. L. Vanek (ed.), Studies Presented to Robert B. Lees by His Students, pages 95-108. Linguistic Research.
Lightner, T. Segmental phonoloy of Modern Standard Russian. Doctoral dissertation, Massachusetts Institute of Technology.
Matteson, E. 1965. The Piro (Arawakan) Language. University of California Press.
Myers, S. 1987. Vowel shortening in English. Natural Language & Linguistic Theory 5(4): 485-518.
Pater, J. and Coetzee, A. W. 2005. Lexically specific constraints: gradience, learnability, and perception. In Proceedings of the Korea International Conference on Phonology, pages 85-119.
Pater, J. 2006. The locus of exceptionality: morpheme-specific phonology as constraint indexation. In University of Massachusetts Occasional Papers 32: Papers in Optimality Theory: 1-36.
Pater. J. 2009. Morpheme-specific phonology: constraint indexation and inconsistency resolution. In S. Parker (ed.), Phonological Argumentation: Essays on Evidence and Motivation, pages 123-154. Equinox.
Prince, A. and Tesar, B. 2004. Learning phonotactic distributions. In Kager, R., Pater, J. and Zonneveld, W. (ed.), Constraints in Phonological Acquisition, pages 245-291. Cambridge University Press.
Rubach, J. 2013. Exceptional segments in Polish. Natural Language & Linguistic Theory 31: 1139-1162.
Rysling, A. 2016. Polish yers revisited. Catalan Journal of Linguistics 15:121-143.
Zonneveld, W. 1978. A Formal Theory of Exceptions in Generative Phonology. Peter de Ridder.