What lay at the bottom of this inconsistence was that the Atsugewi live in a region topographically tributary to the larger Achomawi habitat; that the two tribes were in close association and friendly; and that they followed very similar customs.

The phenomenon of non-reciprocal intelligibility[6][7] is a matter of bilingualism in the smaller and more dependent of two exogamous communities; Kroeber (1925:308) estimated that the Achumawi were ten times more numerous than the Atsugewi.

The aspirated series is contrastive only syllable-initially and probably derives historically from the voiceless-released first member of a consonant cluster, as in the neighboring and possibly related Yana language.

A short centralized vowel [ə ɨ] appears epenthetically between the consonants of certain prefixes, as in lhúpta "let's go!".

Unlike the neighboring and related language Atsugewi, Achumawi has contrastive high and low tones.

[12] Out of an estimated 1500 Achumawi people remaining in northeastern California, perhaps ten spoke the language in 1991, with only eight in 2000.

Louise Davis, who lives in northern California, is almost tearful when she describes hearing people using the language of her Pit River tribe in conversation for the first time.

It was such a powerful, emotional experience that Davis is driven to use flashcards at home with her children and do whatever it takes to preserve the language.