Mid Vowel Alternations in Verbal Stems in Brazilian Portuguese

This paper proposes an alternative analysis for mid vowel alternations in verbal stems in BP, treating them as vowel coalescence, where two input vowels unite into a single output vowel that shares features of its ancestor, in the framework of Optimality Theory (Prince & Smolensky, 1993; McCarthy & Prince, 1995). The vowel coalescence in BP is triggered by the markedness constraint ONSET, which prohibits vowel initial syllables, competing with faithfulness constraints. The ranking of MAX and the markedness constraint ONSET above UNIFORMITY (no coalescence) yields coalescence instead of deletion. For vowel neutralization in BP, I assume the typology of height contrasts in relation to stress proposed by Beckman (1997) and McCarthy (1999); this typology needs to be adapted for Portuguese, since Portuguese has a seven vowel system. In addition, the faithfulness constraint IDENT-SUFFIX is introduced to explain leftward coalescence since coalescence in BP does not occur in locally adjacent segments.


Introduction
This paper discusses mid vowel alternations in Brazilian Portuguese (henceforth BP) in the framework of Optimality Theory (OT, Prince & Smolensky, 1993;McCarthy & Prince, 1995).
In this paper, I will present an alternative analysis of verbal stem alternations in BP, treating them as vowel coalescence, where two input vowels unite into a single output vowel that shares features of its ancestor, in the perspective of the Correspondence Theory (McCarthy & Prince, 1995).Vowel coalescence is triggered by the markedness constraint ONSET, which prohibits vowel initial syllables, competing with faithfulness constraints.In addition, this analysis dispenses with the underspecified mid vowel in UR, which is postulated in the derivational analyses.

The Facts
In BP, mid vowels contrast phonemically in stressed syllables in non--verbs, as shown in (1): (1) a. s [ ]de "headquarters" s[é]de "thirst" b. av [ ] "grandmother" av[ó] "grandfather" However, when mid vowels are in unstressed position, as in the morphologically complex words in the second column of (2a, b), the contrast is obliterated by a vowel neutralization rule (cf.Wetzels, 1991Wetzels, , 1992Wetzels, , 1995) ) the lower mid vowels are realized as the upper mid vowels: (2) a. b [ ] i) in 1 st conjugation verbs (a-themes), the vocalic quality of the mid vowel is determined by a vowel neutralization rulelow mid vowels occur in stressed position and high mid vowels occur in unstressed position; j) in 2 nd conjugation verbs (e-themes), upper mid vowels occur in stressed position, when the theme vowel is truncated, as well as in non--stressed position, and otherwise low mid vowels occur in the stressed position; l) in 3 rd conjugation verbs (i-themes), in the forms that do not realize their theme vowels, high vowels occur instead of mid vowels, regardless of stress, as in s[í]rvo, s[i]rvámos.
In previous derivational analyses (Harris, 1974;Quicoli, 1990;Petrucci, 1992) mid vowel alternations in verbal stems are accounted for by rules of Truncation and Vowel Harmony, where Vowel harmony accounts for the spreading of the aperture features ([high] and [ATR]) from the theme vowel to the mid vowel in the last syllable of the verb root.Truncation deletes the theme vowel.The resulting derivations for some representative verb form are illustrated in (4): (4) a. mv e + o -> móvo "to move" 1st person singular present b.mv e + a -> móva "to move" 3rd person singular present c. srv i + o -> sírvo "to serve" 1st person singular present drm i + o -> dúrmo "to sleep" 1st person singular present d.srv i + a + mos -> sirvámos "to sleep" 1st person plural present Wetzels (1995) argues, in an autosegmental analysis, that the truncation rule and the vowel harmony rule are treated as one simultaneous processthe truncation rule leaves the aperture node floating in a case of a feature stability 1 .This floating node docks to the lower mid vowel of the verbal stem.Wetzels' rules are quoted in ( 5) and ( 6).


Operation: Delete the left V Open (6) Vowel Harmony (VH, cf.Wetzels, 1995: 23) Target: [+Open3] The Truncation rule deletes the theme vowel before a vowel-initial suffix, but the aperture features stay behind.These features are then spread to the mid 1 In Petrucci (1992), the features of the theme vowel that are stable under deletion are [ATR] and [high].The phenomenon of feature stability was first discussed by Goldsmith (1976) to explain tone stability (see also Pigott (1987;1992) for nasal stability).We assume the morphological structure of Verb as in (Câmara, 1970) [móvu] "must" 3rd person plural "to move" 1st person singular present indicative present indicative

Vowel Coalescence in OT
In this section, I will reanalyze the BP mid vowel alternations in verbal stems as a result of the interaction of universal constraints, in the framework of OT, as proposed in Prince & Smolensky, (1993) and McCarthy & Prince (1995).Before entering into this discussion, let me recall some relevant constraints that have been proposed in other OT studies: (12) MAX(F) A feature F present in the Input must have a correspondent in the Output.

Vowel Neutralization
The Portuguese vowel coalescence occurs with lower mid vowels, as shown in section 2. According to Câmara (1970) and Wetzels (1992Wetzels ( , 1995)), there are seven vowels in stressed syllable ([i, e, , a, , o, u]), five vowels in pretonic syllable ([i, e, a, o, u]), and three vowels in word final unstressed syllable ([i, a, u]).Vowel neutralization has been treated as positional faithfulness in OT (cf.Beckman, 1997).For vowel neutralization in BP, I assume the typology of height contrasts in relation to stress proposed in McCarthy (1999).This typology needs to be adapted for Portuguese, since Portuguese has a seven vowel system, for which I will assume the feature definitions as given below: This system reduces to five vowels in pretonic unstressed syllablesthe mid vowels occur in pretonic syllables and in the stressed syllable.In addition, the underlying mid vowels neutralize to high vowels in unstressed word final position.

Mid Vowel Alternations in Verbal Stems in Brazilian Portuguese 91
The phonemic contrast in stressed position can be explained by introducing the markedness constraint *[-ATR, -LOW, -HI]3 , which prohibits lower mid vowels (*/) in the output, interacting with the faithfulness constraints IDENT STR (ATR) and IDENT STR (HEIGHT).The ranking of IDENT STR (ATR) and IDENT STR (HEIGHT) above */ guarantees the surface contrast of mid vowels in the stressed positon, as shown in tableaux (15a) and (15b).In addition, tableau (16b) shows that IDENT(HEIGHT) outranks IDENT (ATR) to eliminate a second candidate as optimal output.
In unstressed word final position, mid vowels neutralize to high vowelsthe optimal output violates the faithfulness constraint IDENT(HEIGHT) which interacts with the markedness constraint *MID] which forbids mid vowels in unstressed word final positon (*MID]  is a positional markedness constraint).The ranking of *MID]  above IDENT(HEIGHT) results in high vowels 4 , as shown in tableau ( 17):

Vowel Coalescence in OT
In Wetzels' analysis, Vowel harmony in BP is triggered by Truncation: the ATR and Height features of the theme vowel spread to lower mid vowels in verbal stems and then the theme vowel is deleted.From the point of view of OT, vowel harmony in BP can be treated as vowel coalescence (cf.McCarthy & Prince (1995), McCarthy (1999)).
The following examples show the effect of vowel coalescence in BP. ( In (18a) and (18b), the lower mid vowels changes to high, assimilating the height feature of the thematic vowel, whereas in (18c) and (18d) a lower mid vowel assimilates the [ATR] feature of the thematic vowel.Vowel Harmony is only active in the 2 nd and 3 rd conjugations.The lower mid vowel in the 1 st conjugation forms is the regular outcome of the neutralization of stressed mid vowels in verbs, which yields lower mid qualities.
In the framework of OT, truncation is explained by the markedness constraint ONSET.This markedness constraint forces the hiatal V + V to become a single syllable, through processes like Deletion, C-Insertion, Diphthongization or Coalescence in diferent language.In the case of the BP vowel alternations under discussion, hiatus is resolved through Coalescence.
According to McCarthy (1999), the constraint ranking MAX >> UNIFORMITY leads to coalescence rather than deletion and there are two possible types of coalescence -IDENT-Perspective Coalescence and MAX--Perspective Coalescence. 4In BP, the word final high vowels realize phonetically as [+ HI, -ATR] -[, ].

Mid Vowel Alternations in Verbal Stems in Brazilian Portuguese 93
In IDENT-Perspective Coalescence, an output segment has two input correspondents and it must be featurally faithful to both.In other words, fusion is total without deletion, as in Sanskrit and Korean (McCarthy, 1999), *NC (Pater, 1995).
Candidate (19a) looks like deletion, but formally it is distinct from MAX violation as indicated by the numerical subscripts.The ranking IDENT(+HI) >> IDENT(-Hi) favors preservation of High (from /i/) in the coalesced candidatepreferring candidate (19b) to candidates (19a) and (19c).The tableaux (21)(22) show the full interactions of constraints related to vowel coalescence in BP.In tableau ( 21), the candidate (21b) violates the highly ranked ONSET.Furthermore, the highly ranked MAX excludes (21a) candidates, in which the theme vowel is deleted.The ranking of IDENT(+ATR) above UNIFORMITY selects the candidate (21d) as optimal output, which changes the low mid vowel of verbal stem to upper mid vowel.
Seung-Hwa Lee The tableaux ( 21) and ( 22) show that the constraint IDENT (+F) must outrank the faithfulness constraint IDENT STR (ATR), which preserves the [ATR] feature in stressed position.
But this IDENT-Perspective Coalescence in BP predicts that the wrong candidate is optimal, when mid vowel contrasts in stressed position are considered.In section 2, I showed that the faithfulness constraint IDENT STR (ATR) and IDENT STR (HEIGHT) dominate the IDENT(ATR) and IDENT(HEIGHT).If the IDENT STR (ATR) dominates the IDENT(+ATR), the candidate (23c) is the optimal output, since the real optimal candidate (23d) violates the IDENT STR (ATR).( 23) McCarthy (p.c.) suggests that the positional faithfulness constraint IDENT STR (ATR) should be two distinct constraints -IDENT STR (+ATR) and IDENT STR (-ATR), as IDENT(+ATR) and IDENT(-ATR) are distinct constraints.In (24b), IDENT STR (-ATR) is violated, because an output stressed [+ATR] vowel has an input correspondent [-ATR].In (24a), IDENT STR (+ATR) is violated, because an output stressed [-ATR] has input correspondant [+ATR].So if IDENT STR (+ATR) dominates IDENT STR (-ATR), the candidate (24b) is selected as optimal. (24) In MAX-Perspective Coalescence, there is a deletion by MAX (segment) violation and some features of the deleted host remain and dock to a new host.This analysis is similar to the idea of autosegmental analysis.The basic idea of this analysis is very similar to the IDENT-Prespective Coalescence, but the constraint MAX(F) replaces IDENT(F).The tableaux ( 25) and ( 26) show that the ranking of MAX (+F) above MAX (-F) guarantees the optimal output in BP.The features [+Hi] and [+ATR] of the deleted theme vowel dock to a lower mid vowel, yielding [i] and [e].In this analysis, the constraint UNIFORMITY is less important, but the high ranking constraints MAX(+F) and ONSET have crucial role to determine vowel coalescence in BP.
In relation to the stressed position theses constraints also dominate the positional faithfulness constraints IDENT STR (HEIGHT) and IDENT STR (ATR).
(28) 1st person singular of present indicative m 1 ve 2 +o 3 MAX(+ATR) ONSET IDENT STR (HEIGHT) The tableau (28) shows that the ranking IDENT STR (HEIGHT) above IDENT STR (ATR) guarantees the optimal candidates (28d) over the candidate (28c).This means that the mid vowel is preserved, when the deleted theme vowel is non-high.
In tableau (29), the candidate (29b) violates the highly ranked ONSET.Furthermore, the highly ranked MAX (+HI) excludes drmo/dormo candidates, in which the theme vowel is deleted.Since there is no coalescence in the forms (29a) and because in (29c) the resulting mid vowel only preserves the ATR feature of the deleted theme vowel, these forms represent non-optimal candidates.MAX(+HI) above IDENT STR (HEIGHT) selects the candidate (29d) as optimal output, which changes the low mid vowel of verbal stem to high vowel.
( Usually, coalescence occurs between two adjacent segments.However, in Portuguese vowel coalescence does not occur in adjacent vowel pairs.Instead the aperture features of the theme vowels spread leftwards towards the verb stem.According to McCarthy (1999) coalescence occurs only in locally adjacent segments, as in Korean, French, Indonesian, Navajo, and Sanskrit.How then can it be explained that in BP the same process applies to non--adjacent segments?What is the motivation for leftwards feature spreading?From this point of view, the constraint interactions presented in (29) predict that a better candidate would be one in which coalescence effects contiguous vowels, as shown in tableau (31).How can the leftward feature spreading be explained in OT analysis?
In an autosegmental analysis, feature spreading is well motivated as a phonological operation: the floating features spread to an lower mid vowel in verbal roots, not to the inflectional suffix.
In OT, the set of possible inputs is universal and unrestricted by the principle of Richness of the Base (Smolensky, 1996) -There are no language--particular restrictions on the lexicon.The contrasts are derived by interactions of OT constraints in the output.The mid vowel contrast is Mid Vowel Alternations in Verbal Stems in Brazilian Portuguese 97 unpredictable in non-verbal words and predictable in verbal words in BP.The tableau (32) shows that an ungrammatical output is chosen as optimal, when the vowel quality of input vowel is upper mid.The real optimal output [mve] violates the highly ranked constraint IDENT STR (HEIGHT/ATR).32) show that in BP verbal stems the input quality of a mid vowel quality has to be lower mid, not a underspecified mid vowel.
Then, how can the OT analysis interpret the prediction presented in autosegmental analysis?
One possible solution to this problem is to introduce the following faithfulness constraint.
(33) IDENT-SUFFIX A suffix must have a correspondent in the output.
This constraint prohibits the alternation of suffix, when the suffix is attached to the stem.This faithfulness constraint interacts with MAX(HEIGHT/ATR) and ONSET, forcing the deletion of thematic vowel by ONSET and spreading floating features to root final mid vowel by MAX(HEIGHT/ATR).Tableau (34) shows that the candidate (34a) is excluded by ONSET.(34b) and (34d) are non-optimal because they violate the highly ranked IDENT-SUFFIX.Finally the candidate (34c) is optimal, although it violates the lowest ranked UNIFORMITY and IDENT STR (HEIGHT) and IDENT STR (ATR).The unstressed word final high vowel is the result of neutralizaton, not of coalescence.

Conclusion
In this paper, I have analyzed the mid vowel alternations in verbal stem in the framework of OT.In OT, the mid vowel alternations of verbal stem in BP are treated as vowel coalescence, where the ranking of MAX and markedness constraint ONSET above UNIFORMITY (no coalescence) yielding coalescence instead of deletion.In addition, I have presented two possible analyses account for BP stem vowel alternations: IDENT-Perspective Coalescence and MAX-Perspective Coalescence (Cf. McCarthy, 1999).In IDENT-Perspective Coalescence analysis, BP coalescence is motivated by Onset >> Uniformity and Ident (+F) has a crucial role in determining the correct output.In MAX--Perspective Coalescence analysis, BP coalescence is triggered by the deletion of the theme and the high-ranked Max (+F) plays a crucial role in the selection of the optimal candidate.This approach is very similar to the autosegmental analysis presented in Wetzels (1995).I will not discuss here which analysis is better for BP coalescence -I will leave this question open for future studies.
The faithfulness constraint IDENT-SUFFIX was introduced to explain the leftward coalescence since the coalescence phenomenon in BP does not occur in locally adjacent segments.In addition, I have proposed an alternative analysis for vowel neutralization in BP, by adopting the typology of McCarthy (1999).Some constraints related to ATR features are added to explain BP vowel neutralizations.

( 8 )
UNIFORMITY "No Coalescence" No element of the Output has more than one correspondent in the Input.(9) ONSET Syllables must have Onset (*  [V).(10) IDENT(F) Correspondent segments have identical values for the feature F. (11) MAX (anti-deletion) Every element of the Input has a correspondent in the Output candidate.