Il y atrois-quarts de siècle, George Cœdès a montré que huit des termes du cycle duodécimal khmer étaient apparentés aux noms usuels des animaux correspondants en muong (dialecte proche du vietnamien). Aujourd'hui, on peut affirmer que les douze termes du cycle entier, plus 'année', sont des emprunts au vietnamien ancien. Pour chaque terme, on compare les formes modemes, les attestations épigraphiques et les reconstructions dans les langues concernées. Des substitutions de noms d'animaux sont mises en évidence. Les plus anciennes attestations de mots vietnamiens se trouvent dans les anciennes inscriptions khmères.
The Tai language of Qui Châu (northern Nghê An, Vietnam) was until recently one of the least known languages of the Daic phylum. It has an alphabetic orthography which is written vertically in columns from right to left, like traditional Chinese books. The present article, based on materials left by Henri Maspero, gives an overwiew of this writting system, which is ultimately derived from systems used in Siam in the XIVth Century. The Tai language of Qui Châu has a stratum of vocabulary closely related to the Yay branch of southern China. Our hypothesis is that these Tai people represent a Yay group who were forced out of southern China, settled in the Qui Châu area, and were later submerged by the migration of other Tai groups from northern Laos.
The Thai spoken in Vietnam comprises a large number of dialects and uses several systems of writing which can be classified into three sets: (I) the Black Tay, the White Tay and the Tay Dèng: (2) the Tay Yo and (3) the Lai Pao. Their common origin allows an historical and comparative study which sets up the correspondence between the written symbols with the phonemes of proto-Thai, the only way to understand the development of these writing systems and the connections between the written forms and their sounds. The loans and the phonetic changes have led to the invention, the deletion and the transfer of the phonetic values for these graphie symbols.