From The Art and Popular Culture Encyclopedia
Pirahã is the only surviving dialect of the Mura language, all others having become extinct in the last few centuries, as most groups of the Mura people have shifted to Portuguese. Suspected relatives, such as Matanawi, are also extinct. It is estimated to have between 250 and 380 speakers. It is not in immediate danger of extinction, as its use is vigorous and the Pirahã community is mostly monolingual.
The Pirahã language is most notable as the subject of various controversial claims; for example, that it provides evidence for linguistic relativity. The controversy is compounded by the sheer difficulty of learning the language; the number of linguists with field experience in Pirahã is very small.
The Pirahã language is one of the phonologically simplest languages known, comparable to Rotokas (New Guinea) and the Lakes Plain language Obokuitai. There is a claim that Pirahã has as few as ten phonemes, one fewer than Rotokas, but this requires analyzing Template:IPA as an underlying Template:IPA. Although such a phenomenon is odd cross-linguistically, Ian Maddieson has found in researching Pirahã data that Template:IPA does indeed exhibit an unusual distribution in the language.
The 'ten phoneme' claim also does not consider the tones of Pirahã, at least two of which are phonemic (marked by an acute accent and either unmarked or marked by a grave accent in Everett), bringing the number of phonemes to at least twelve. Sheldon (1988) claims three tones, high (¹), mid (²) and low (³).