The phonetics and phonology of non-modal vowels: a cross-linguistic perspective

101

vowels, unstressed vowels and perhaps low toned vowels, are most susceptible to

devoicing in final position.  The gradual nature of the decline in subglottal pressure

throughout the utterance is also compatible with the fact that  devoicing  in  many

languages (e.g. Acoma, Big Valley Shoshoni,  Turkana,  Nyangumata)  affects  not

only the final vowel but also may extend farther back from the end of the domain in

gradient fashion.

Interestingly, the decline  in  subglottal  pressure  is  in  direct  competition  with

another common cross-linguistic property of final position:  final lengthening (cf.

Wightman et al. 1992).  A priori one might expect, by analogy with the blocking of

devoicing by phonemic long vowels and accented vowels in final position in many

languages, that the additional phonetic length of final vowels would block devoicing.

However, the gestures associated with final lengthening  are  different  from  those

associated with other types of lengthening.  Final lengthening does not involve an

increase in gestural magnitude, unlike lengthening associated with accent (Beckman

et al. 1992) or presumably, phonemic length.  It is thus not surprising that, whereas

phonemic long vowels and accented vowels inhibit final devoicing, final lengthening

typically does not.  In fact, final voiceless vowels, like their non-final counterparts,

are usually described as being quite short, shorter than even non-final voiced vowels.

Thus, the subglottal  pressure  decline  not  only  inhibits  final  lengthening,  it  also

appears to induce final shortening.    

5. 

ARTICULATORY

/

AERODYNAMIC VS

. 

PERCEPTUAL FACTORS

.    In  summary,  a

combination of articulatory overlap and the decline in subglottal pressure in final

position  account  for  many  of  the  devoicing  patterns  found  cross-linguistically.

Interestingly, the articulatory and aerodynamic factors which induce devoicing are in

conflict  with  the  perceptual  factors  militating  against  devoicing.    Devoicing  of

vowels  is  articulatorily  and  aerodynamically  natural  under  certain  conditions  as

shown in the last section; however, voiceless vowels are perceptually less salient than

voiced vowels as argued in section 2.  The conflict between articulatory/aerodynamic

factors and perceptual considerations is evident when we compare Hupa, in which

long but not short vowels devoice, with the  many  languages  (e.g.  Cheyenne)  in

which short but not long vowels undergo devoicing.  This conflict can be modeled in

the grammar by assuming different ranking of the relevant constraints in the two

language types.  In Hupa,  *N

ON

-

MODAL 

S

HORT 

V

OWELS 

is  ranked  above  the

relevant constraint forcing devoicing, whereas, in Cheyenne, *N

ON

-

MODAL 

S

HORT

V

OWELS 

is  ranked  lower  than  the  relevant  constraint  driving  vowel  devoicing

between  voiceless  consonants.    By  shifting  the  rankings  slightly  we  get  other

patterns.  For example, the Acoma pattern, in which both short and long  vowels

devoice, is derived by ranking both *N

ON

-

MODAL 

S

HORT 

V

OWELS 

and  *N

ON

-

MODAL 

L

ONG 

V

OWELS 

below the constraint driving devoicing.  If, on  the  other

hand,  we  rank  both  *N

ON

-

MODAL 

S

HORT 

V

OWELS 

and  *N

ON

-

MODAL 

L

ONG

V

OWELS 

above constraints requiring devoicing, we get a language without devoicing

of any vowels.  The rankings which generate the attested patterns are shown in (1).

For expository purposes, the set of constraints which force devoicing are collapsed

as a single constraint devoice.  Although space limitations preclude doing so in this

paper, these constraints can easily be divided into narrower (or broader, as in Hupa)

constraints capturing the further asymmetries discussed in this paper.   

(1) Ranking

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