Mora Insertion in Tetso ̨́ t’ıné: Apparent cases of under-and overapplication

Tetsǫ́t’ıné is a dialect of Dëne Sųłıné (ISO: CHP) spoken in Canada’s Northwest Territories. In Tetsǫ́t’ıné, prefix vowel length is subject to a complex set of conditions. The basic generalization is that when a consonant is deleted at the same level that a preceding prefix is added, a short vowel results; whereas when a prefix is added first, and an intervocalic consonant deletes at a later level, a long vowel results (Jaker 2022). This paper addresses two apparent counterexamples to this generalation—that is, cases of exceptional long and short vowels, which may be thought of as overapplication or underapplication of mora insertion. In optative paradigms, the consonant ɣ lenites to w in the singular forms at Level 3. w then deletes at Levels 4 and 5, resulting in a short vowel following Level 4 and 5 prefixes. Conversely, the prefixes θe and ɲe are preceded by a null vowel lexically pre-associated to a High tone. This null vowel acquires a mora at Level 2, thus resulting in an exceptionally long vowel when the initial consonants of θe and ɲe are deleted following a Level 4 prefix.


Background on Tetsǫt'ıné
Tetsǫt'ıné (Yellowknife) is a dialect of Dëne Sųłıné (ISO: CHP) spoken in Canada's Northwest Territories. Tetsǫt'ıné was first documented in a wordlist published by Haas (1968). The Tetsǫt'ıné dialect, along with the Yellowknives Dene themselves, was declared extinct by Gillespie (1981). In spite of this, recently a dictionary (Cardinal, Jaker & Cardinal 2021) and a verb grammar (Jaker & Cardinal 2020) of this dialect have been published. A map of northern Dene languages is given in (1). Note that Tetsǫt'ıné is separated from Dëne Sųłıné by a dialect boundary.
(1) Northern Dene language map (Kari 2020) Tetsǫt'ıné, like all Dene languages, is a templatic, prefixing language. Its morphology could be characterized as underlyingly agglutinating, but surface-fusional: underlying forms consist of discrete prefixal elements with clearly identifiable meanings, but these prefixes often fuse on the surface due to processes of intervocalic consonant deletion and vowel coalescence. Tetsǫt'ıné has four contrastive tones (High, Low, Rising, Falling), contrastive vowel length, and quantity-sensitive iambic stress (Jaker & Howson 2022).

Lexical Phonology of Tetsǫt'ıné
The Tetsǫt'ıné verb is templatic and prefixing (Jaker & Cardinal 2020). However, these template positions seem to form a layered structure. Applying level ordering to the Dene verb was first proposed by Hargus (1988), for the northern Dene language Sekani. Previous Lexical Phonology work on Tetsǫt'ıné has argued for a total of 6 levels (5 lexical levels + the postlexical level) (Jaker & Kiparsky 2020, Jaker & Cardinal 2020, Jaker 2022, as shown in (2). The numbers at the bottom of (2) are template positions.
(2) Lexical Phonology model of Tetsǫt'ıné (Jaker & Kiparsky 2020) Under this model, different prefixes are assigned to different levels. A list of which prefixes are assigned to which levels is given in (3).
(3) Examples of prefixes assigned to different levels Level Level 6 Level 5 Level 4 Level 3 Level 2 Level 1 Template positions 000 -0 1 -4 5 -6 6 -7 8 -12 13 The level to which a prefix belongs determines the phonological processes in which it will participate. A morpheme belonging to Level 1 will participate in the phonological processes of all levels, 1-6. A Level 2 prefix will participate in the processes of Levels 2-6, but not Level 1. A Level 3 prefix will participate in the processes of Levels 3-6, but not 1 and 2, etc.
In Tetsǫt'ıné, as in most other Dene languages, most of the morphophonemics involve intervocalic consonant deletion, and the vowel coalescence that results from that. Different consonants delete (or lenite) at different levels. A table summarizing which consonants delete (or lenite) at which levels is given in (4).
(4) Summary of which consonants delete at which levels

Systematic Underspecification
The essential puzzle concerning Tetsǫt'ıné prefix vowel length is this: All long vowels in prefixes are the result of intervocalic consonant deletion; however, not all cases of intervocalic consonant deletion result in a long vowel. Whether intervocalic consonant deletion results in a long or a short vowel depends on a combination of two factors: the consonant which was deleted, and the level to which the preceding prefix belongs. In my recent NLLT article (Jaker 2022), I argued that the key generalization is when consonant deletion occurs, relative to affixation. This is stated in (5).
(5) Relationship between intervocalic consonant deletion and vowel length (Jaker, to appear) a) When an intervocalic consonant C2 is deleted at the same level that a preceding prefix is added, a short vowel results: /V1-C2V3/ ® [V1,3]. b) When V1 is added first, and C2 is deleted at a later level, a long vowel results: An illustration of this generalization is given in (6).
(6) The Level 5 prefix ʃé followed by both w and ɣ In (6), the prefix ʃé is a Level 5 prefix. w deletes at Level 5, while ɣ deletes at Level 6. Therefore, when w deletes at Level 5, a short vowel results. When ɣ deletes at Level 6, the preceding vowel has already acquired a mora, and so a long vowel results.

Underapplication: Optative paradigms
The optative prefix /ɣu/ is a Level 2 prefix. Our analysis so far predicts that if /ɣu/ is preceded by a Level 4 or 5 prefix, a long vowel should result. Instead, we observe short vowels in the singular forms, and long vowels in the plural forms, as shown in (7)-(8), with the Level 5 prefixes ʃé and ná.

Lexical Phonology analysis
To account for these data, I propose two rules: a ɣ to w lenition rule, and a w deletion rule. The ɣ to w lenition rule is shown in (11). This rule is motivated by the need to have high-sonority onsets in prosodically weak positions (González 2003). Subsequently, w is deleted at Levels 4 and 5, as shown in (12).
(11) ɣ to w lenition rule (Level 3) * (s s) ɣ ® w / __ u . C V "ɣ lenites to w before u, in the onset of the weak position of an iambic foot." (12) Intervocalic w deletion (Levels 4 and 5) w ® Ø / V __ V "w is deleted in between two vowels." The application of these two rules is illustrated in (13) and (14).

Conclusion
We have examined cases of overapplication and underapplication of mora insertion in Tetsǫt'ıné. In optative paradigms, a rule which lenites ɣ to w applies in prosodically weak position at Level 3, leading to exceptionally short vowels in the singular forms. In the case of the θe and ɲe conjugation markers, a null vowel acquires a mora at Level 2, leading to exceptionally long vowels at Level 4. In both cases, the explanation of surface vowel length involves careful attention to representations, as well as a form's derivational history. This type of explanation is facilitated by the Lexical Phonology framework, where a form's derivational history reflects its morphological structure.