David Stampe and Patricia Donegan
Iambic vs Trochaic Effects in Austroasiatic
In two earlier papers:
http://www.ling.hawaii.edu/austroasiatic/rhythm1983.pdf%20and%20/rhythm2004.pdf, we presented a reconstruction of the holistic structural drift from proto-AA based on the hypothesis that every level of language, from syntax to phonetics, responds to whether the /beginnings/ or the /ends/ of words and phrases are set to the right-branching beats and bars of our mentally generated rhythmic score. At the level of words, we contrasted iambic proto-AA /bəˈluː/ vs trochaic proto-Munda /ˈbəlu/ ‘thigh’, but argued that in terms of rhythmic beats they are not just reversed but are totally different rhythmic settings. The difference is seen in typical reflexes, Mon-Khmer /ˈphlau/ vs Munda /ˈbulu/ – Mon-Khmer with aphesis, consonant shift, diphthongization, and perhaps register or tone, but Munda with simple harmony.
In this presentation, we will cite a variety of evidence that iambs are not integral rhythmic units, and that it is word isochrony rather than iambicity that makes MK and SE Asian phonology so volatile. With word isochrony, as in early English, trochaic words can be just as volatile as iambic ones. Munda languages, which due to the highly variable length of their words must use syllable or mora isochrony, have very stable phonologies. This is not due just to their trochaic structure, because the most frequent Munda word structure, CVCVC, is usually spoken as an iamb, and yet only in Gta’, the only Munda language with word-isochronous tendencies, have such words suffered phonological effects resembling those of Southeast Asian languages.