Excerpt from change request document:
Based on phonological, grammatical, and lexical differences (see attached documentation), there are two linguistic variants in this language which make it difficult to convert materials in one variant directly to the other. When speakers of the two variants try to communicate in their language, they have so much trouble understanding each other that they usually use Spanish instead. Furthermore, there are several words that appear to be the same in the two variants that show significant semantic shift. There is approximately 85% comprehension between the two variants, which makes the speakers think they should be able to communicate in their language, but in fact they usually find it impossible. This has been confirmed by linguistic and sociolinguistic studies (see bibliography).
In the cultural realm, the Eastern variant has conserved more of their traditional beliefs than has the Western variant, where only some very elderly speakers still know them. Another factor has been the invasion of the Eastern variant by migrating speakers of Southeastern Tepehuan (stp), causing cultural and linguistic changes. In the Western variant, there are fewer such influences, especially in the communities in Durango State (San Agustin de Buenaventura, Curachitos de Buenavista, San Diego, Tepetates II (Berenjenas), Alacranes and Tepalcates). Except for Tepalcates, all these communities still use the language in all aspects of daily life, probably because there are few other linguistic influences in their isolated area. They even use Nahuatl when they talk on their "walkie talkies." Thus this area can be considered the heart of the ethnic group, because there the language and culture are preserved.
There are, however, some trends toward moderization that threated their cultural identity.
In Nayarit State, the same Western variant is spoken in four places (Santa Cruz, La Laguna, Mesa de las Arpas, and El Duraznito). The language is more threatened there, since these four communities have fewer speakers and are surrounded by large communities of Cora and Huichol speakers. This has caused the loss of the language in some parts to the extent that symptoms of language death are evident. In the schools of these four communities, Nayarit State has created a program to promote the use of the language, including training teachers in the language and in positive attitudes toward it, but in the homes it is often not spoken by the children, although they still understand it. The older traditional authorities also favor the creation of materials to promote the use of the language.