proto-southwestern-tai revised: a new reconstruction - seals 22

Proto-Southwestern Thai 129
outcome for PSWT *ʔɤk strikingly is -ʔɯk, the second part of the Thai ‘hiccups’. Note that
the o ~ ɯ alternation is quite common in spoken Lao, e.g. mot D1 ~ mɯt D1 ‘all gone’.
2.4.4 In support of contrastive length
The PT vowel system has been the subject of investigation for decades but problems still
remain. The PSWT vowels, in contrast, have not been as controversial. Li (1977) and
Sarawit (1973) agree in reconstructing vowel length for the high vowels and *a. They also
share the view that there is a contrast between short mid vowels and long low vowels, i.e.
*e and *ɛː. However, recently doubts on these interrelated aspects of the vowel system
have been expressed (Jonsson 1991; Luo 1997). Here I show that evidence form modern
dialects support the position that vowel length was contrastive in PSWT.
While opting not to reconstruct a vowel length contrast in PT, Li (1977) allows for
a quantity contrast in PSWT. This choice is in line with Sarawit (1973), whose
reconstruction only differs from that of Li in details of the changes involved. In contrast,
Jonsson (1991) treats vowel-length as secondary. After excluding secondary lengthening in
daughter languages such as Thai and Southern Tai (Diller 1979; Hartmann 1976), the
patterns of tone mergers and splits show that all vowels were long in open syllables but
vowel-length was contrastive on closed syllables. From the perspective of Li’s PT, long
vowels in closed syllables in SWT varieties developed from earlier diphthongs or
triphthongs.
Although short and long vowels in cognates in modern dialects that have quantity
distinction are almost in complementary distribution, the unpredictability of the reflexes
favors a reconstruction of PSWT with contrastive vowel length. If vowel length had not
been phonemic, conditioning environments should be identifiable. Moreover, languages
that have vowel lengths agree in most cases. When they do not, syllable structure or tone
can be identified as the conditioning environments. In the Yong cases presented here, the
nasal codas are responsible for the neutralization of vowel length, i.e. pre-nasal shortening.