66 consonant cluster are also affected. All verb-final consonants and consonant clusters may be palatalized
by the clause-type palatalization morpheme. Alternative models of feature geometry relative to the sources of secondary palatalization in Isthmus
Mixe will then be considered. It will be shown that the vowel-place models proposed by Hume 1994, Ní Chiosáin 1994 and Clements and Hume 1995 more adequately represent the Isthmus Mixe data than
articulator models proposed by Sagey 1986 and Halle, Vaux, and Wolfe 2000.
5.2.1 Isthmus Mixe nasal place assimilation and voicing spread
Before considering detailed analysis of palatalization, however, the usefulness of the feature-geometric approach is illustrated by examining a more straightforward phonological process in Isthmus Mixe, nasal
place assimilation. Widespread in the world’s languages, nasal place assimilation is also found in the Mixe languages Crawford 1963:44–45, Van Haitsma [Dieterman] and Van Haitsma 1976:13–14. An example
in Isthmus Mixe is shown in the examples related to the verb tuN to work, in which N
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assumes the place of articulation of a following a plosive section 2.3.2.2: The default articulation is alveolar [n],
occurring word final as in tuN 1 and between vowels as in tuN‚p 2.
1 tuN
[tun] he worked
2 tuN‚p [tun‚p]
he should work 3
tuNp [tumb]
he works 4
tuNt‚k‚»j [tund‚g‚»j]
he began to work 5
tu»Nk [tu»¯g] work noun
In addition to place assimilation, the nasals spread voicing to a following plosive. Although sonorants are considered to be underspecified for [voice] in many languages, in Isthmus Mixe [+voice] must be
specified because of the voicing spread of N. Nasal place assimilation and voicing assimilation processes may be described using a feature tree, such
as that developed by Halle 1992. This feature tree is used to formulate common sound change processes such as assimilation, whether single-feature, complete, or partial Kenstowicz 1994:150–158. In Isthmus
Mixe, the examples 3–5 of partial assimilation illustrate the utility of the feature tree in which the soft palate tier, oral place tier and laryngeal tier are all separate figure 5.1. In the case of Isthmus Mixe nasal
N, the oral place node of the consonant that follows N spreads leftward to associate itself with the root node of N, and the laryngeal node of N [+voice] spreads rightward to the laryngeal node of the
following consonant.
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In Isthmus Mixe, the archiphoneme N occurs in morpheme-final position and in the morpheme-final cluster Nk [
¯g]. It contrasts with n- ‘first person’ and m- ‘second person’ which are word-initial morpheme prefixes. The phoneme m occurs in morpheme-final position and contrasts with N by not assimilating to a following plosive.
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N C | |
X [+cons]
[+son] X
[+cons] [-son]
|
oral place
| X
laryngeal laryngeal
| =|=
glottal glottal
| |
[+voiced] [-voiced]
soft palate
|
[+nasal] [-cont]
Figure 5.1. Isthmus Mixe nasal place and voice assimilation. Feature geometry allows this two-way assimilation to be shown in one diagram, reducing redundancy
and expressing the simultaneous nature of these processes. The phonological rules recognize the natural class at the oral place node, while the other features remain independent. This model is both phonetically
faithful and phonologically relevant, a simple, yet fully adequate and elegant explanation of the data.
5.3 Sources of Isthmus Mixe palatalization
