Allographic patterns in Tai Ahom Manuscripts and their relations to Proto-Southwestern Tai Phonemic contrasts

This research aims to (i) establish the graphemes in the Ahom script by doing a graphemic analysis of the script, (ii) to examine the conditioned and unconditioned allographic patterns in the Ahom manuscripts and (iii) to interpret the variation patterns in relation to the Proto- Southwestern Tai phonemes. The Ahom manuscripts show variation patterns that can be used to classify the manuscripts into two sets (i) Set A which comprised of manuscripts having either one of the forms showing variation and (ii) Set B on the other hand consisted of manuscripts which show interchangeable use of both the forms in variation. As for correspondence of the graphemes to Proto-Southwestern Tai, the unconditioned allographic variation of the graphs j and ny show merger of *ɲ- and *hɲ- with *j-. Similarly, the unconditioned allographic variation of v and w shows the merger of *au and *aau. Unconditioned graphemic variations are also found between <b> and <m> and between <n> and <d>. However, these graphemic variations are confined only to a specific set of words corresponding to *ʔb- and *ʔd- suggesting retention of the contrast between PSWT preglottalized stops and their corresponding nasals. The conditioned allographic variations of the graphemes <b> and <m> failed to show retention of Proto- Southwestern Tai phonemic contrasts. Both the allographs b and w of the grapheme <b> and the allographs m and ṃ of the grapheme <m> correspond to the same Proto- Southwestern Tai phonemes *w- , *hw- and *m-, *hm- respectively, thus refuting the hypothesis that conditioned allographic patterns show retention of the Proto-Southwestern Tai phonemic contrasts. In contrast, conditioned allography of the vowel graphemes <i> and <u> show a merger of the Proto- Southwestern Tai phonemes *i, *ii and *u, *uu respectively.