Quechua
The neologism 'Quechuan' is synonymous with Quechua, the name of the most widely spoken Native American language family of the indigenous peoples of the Americas, with a total of probably some 6 to 8 million speakers (estimates vary widely). Quechua is spoken across large areas of the Andes of South America, in many regional varieties, which pattern into broad dialect continua rather than clearly definable individual languages.
All Quechua varieties derive from an original single common ancestor language, Proto-Quechua. This first began expanding across the Andes over a millennium ago, however, and changed differently over time in different regions. So today speakers of the most divergent regional varieties of Quechua do not find each other's speech mutually intelligible, the basic criterion that defines Quechua as not a single language but a family of closely related languages. The level of linguistic diversity within the family is similar to that of Arabic or Slavic, and a little less than that within Romance or Germanic.
Individual varieties or 'dialect' regions within the Quechua family are specified by adding the appropriate regional qualification, such as 'Cuzco Quechua', 'Southern Quechua' or 'Ancash Quechua'. In some cases, specific names have become established for individual varieties, such as 'Kichwa' as equivalent to 'Northern' or 'Ecuador Quichua'.
The case of Quechua is analogous to that of Arabic or Chinese, terms popularly imagined to represent a single language, but which also refer to what linguistically are language families whose varieties similarly pattern geographically into dialect continua. The use of regional qualifications to specify individual forms of Quechua is analogous to how this is also done for Arabic or Chinese: to distinguish, for example, Gulf, Lebanese, Moroccan Arabic or indeed Classical Arabic; or Mandarin from Cantonese forms of Chinese. Just as there has been no need to invent separate terms 'Arabican' or 'Chinesean', there is no need for a separate term 'Quechuan', which cannot be usefully distinguished from Quechua.
