Trans-Tocantins languages
The Trans-Tocantins languages are a proposed subgroup of the Northern Jê languages, which comprises four languages spoken to the west of the Tocantins River: Apinajé, Mẽbêngôkre, Kĩsêdjê, and Tapayúna. It is subdivided in a binary manner into Apinajé, spoken to the east of the Araguaia River, and the Trans-Araguaia subbranch, which includes the remaining three languages. Together with the Timbira dialect continuum, the Trans-Tocantins languages make up the Northern branch of the Jê family. The defining innovations of the Trans-Tocantins languages include the replacement of Proto-Goyaz Jê and Proto-Northern Jê "*a -mbə" ‘eat "(intransitive)"’ (as preserved in Canela/Krahô/Parkatêjê "apà", Pykobjê "aapỳ", Panará "-ânpâ") with Proto-Trans-Tocantins "*ap-ku" (> Apinajé "apku", Mẽbêngôkre "aku", Kĩsêdjê/Tapayúna "akhu"). as well as the fortition of Proto-Northern Jê "*j" to "*ĵ" in unstressed syllables (except if preceded by the low vowel "*a"), as shown below.