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

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THE PHONETICS AND PHONOLOGY OF NON-MODAL

VOWELS:  A CROSS-LINGUISTIC PERSPECTIVE

M

ATTHEW 

G

ORDON

University of California, Los Angeles

This paper provides phonetic explanations for a number of asymmetries in the

distribution of non-modal voiced and modal voiced vowels found in a typology

of over 50 languages with non-modal vowels.  The distribution of non-modal

vowels cross-linguistically is argued to result from the conflicting demands of

perceptual salience and articulatory ease; this conflict can be formally modeled in

an constraint-based grammar.

*

 

1. I

NTRODUCTION

. Some languages of the world have vowels characterized by non-

modal  phonation,  e.g.  breathy  voiced  vowels,  voiceless  vowels,  or  creaky

(laryngealized) vowels.  Depending on the language  and  on  the  phonation  type,

these non-modal vowels may either contrast with or be allophonic variants of modal

voiced vowels.  For example, creaky vowels are phonemic in Kedang (Samely 1991)

and Jalapa Mazatec (Kirk et al. 1993), but occur allophonically in the vicinity of

glottalized consonants in many languages, e.g. Georgian and Tzeltal (cf. Crothers et

al. 1979).   Breathy  voiced  vowels  are  phonemic  in  Gujarati  (Fischer-Jørgensen

1967) but occur allophonically in the vicinity of /

h/ in many languages.  Similarly,

voiceless  vowels  contrast  with  voiced  vowels  on  the  surface  in  Turkana

(Dimmendaal 1983), but occur allophonically in Japanese (Han 1961).  

Non-modal vowels have a quite different distribution from modal vowels.  First,

they are quite rare cross-linguistically, both as phonemic segments which contrast

with modal vowels, and as non-contrastive allophones of modal voiced vowels.  For

example, Maddieson’s (1984)  survey  of  317  languages  includes  only  two  with

contrastive laryngealized/creaky voice (Sedang and Southern Nambiquara), two with

contrastive voiceless vowels (Ik and Dafla), and one with phonemic breathy voiced

vowels  (Tamang).    Another  characteristic  property  of  non-modal  vowels  which

differentiates them from modal vowels is their limited distribution.  For example,

voiceless vowels are often limited to word-final position, and creaky vowels tend to

occur adjacent to glottalized consonants. In other languages, non-modal vowels are

the synchronic manifestations of other types of contrasts, e.g. segmental, tonal, or

durational ones.      

Given the limited distribution of non-modal  vowels  relative  to  modal  vowels

there are a couple of basic questions which come to mind.  First, why do non-modal

vowels typically play a limited role in the phonology of most languages?  Second, is

the distribution of non-modal vowels predictable on phonetic grounds?  This goal of

this paper is to provide answers to these questions and to formalize these answers in

an Optimality Theoretic grammar.   

2. T

HE RARITY OF NON

-

MODAL VOWELS CROSS

-

LINGUISTICALLY

.  I conjecture

that the rarity of contrastive non-modal vowels has a perceptual basis; non-modal

vowels are perceptually less robust than modal vowels and are therefore eschewed

by many languages.  It has been shown by Silverman (1995, 1998) that, non-modal

phonation reduces  the  ability  of  vowels  to  manifest  tonal  contrasts  in  a  salient

manner.  Given this fact, it is thus not surprising that many tone languages (e.g.

Jalapa Mazatec) restrict overlap between tonal and phonation contrasts.

However, beyond the inherent incompatibility between non-modal voicing and

tone discussed by Silverman, there is reason to believe that non-modal vowels share

properties which make them inherently less salient than modal vowels, even in the

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absence  of  tonal  contrasts.    This  reduced  salience  can  inhibit  the  recovery  of

contrastive  place  information  in  the  vowel.    Let  us  now  consider  the  acoustic

properties which make non-modal vowels less salient than modal vowels.

First, non-modal vowels are characterized by less overall acoustic intensity than

modal  vowels  as  shown  for  different  non-modal  phonation  types,  e.g.  breathy

vowels in Kui and Chong (Thongkum 1987), creaky vowels in Chong (Thongkum

1987) and voiceless and creaky vowels in Hupa (Gordon 1998).  Decreasing the

acoustic  intensity  results  in  a  decrease  in  loudness,  the  auditory  correlate  of

intensity; it thus follows that non-modal vowels are less salient than modal vowels.  

Furthermore, non-modal voicing often alters the spectral properties of vowels,

including formant structure, as demonstrated instrumentally  for  Kedang  (Samely

1991)  and  Chong  (Thongkum  1987),  and  also  qualitatively  evident  in  many

languages, e.g. those in which vowels in the vicinity of glottal stop and /h/  have

noticeably different qualities than vowels in other environments not associated with

non-modal phonation (cf. Blankenship 1997 for extensive discussion of the spectral

properties of non-modal vowels).  The perturbation of formant structure potentially

makes recovery of vowel quality contrasts more difficult.  In summary, given the

reduced intensity of non-modal phonation  and  its  influence  on  vowel  quality,  it

would thus not be surprising that many languages design their phonologies to limit

the distribution and the role of non-modal vowels.  

In  addition  to  the  general  paucity  of  contrastive  non-modal  vowels  cross-

linguistically, other  language  specific  facts  suggest  that  phonologies  avoid  non-

modal  vowels  for  perceptual  reasons.    First,  breathy  voiced  vowels  in  Kedang

(Samely 1991), and both breathy and creaky vowels in Jalapa Mazatec (Kirk et al.

1993) are phonetically much longer (up to 50% longer) than their modal  voiced

counterparts.  An interesting aspect of Jalapa Mazatec is that non-modal  voicing

does not persist throughout the entire duration of phonemic breathy and glottalized

vowels.  Rather, non-modal voicing occurs principally on the first half of non-modal

vowels; the second half of non-modal vowels is phonetically characterized by modal

voicing.  Acoustic measurements of fundamental frequency and formants suggest

that non-modal voicing is also largely confined to the first  half  of  the  vowel  in

Kedang.  Crucially, Kedang is not a tone language; thus, the realization of  non-

modal  voicing  cannot  be  attributed  to  the  presence  of  tonal  contrasts.    Rather,