- "any language unit that is accorded a separate name by its speakers, regardless of whether it is, technically, a dialect or a language" (Hudson 1976:12)
Another term that comprises the senses of both 'language' and 'dialect' is languoid, but a languoid is any language or group of languages that linguists might be interested in, so its meaning is much broader.
The term isolect was coined by Hudson in 1976. When working on the classification of some languages and dialects in Borneo (the Barito group), in many cases where he could not decide a priori if a variety that he encountered was a language in its own right or a dialect of another language. So he coined the term isolect for such language varieties.
The term has been used quite a bit in Bornean and Malayic linguistics, but has also appeared with reference to non-Bornean and non-Malayic (and even non-Austronesian) languages, as well in theoretical works.
The term has been found very useful for working on languages of Indonesia, since very often people refer to their language with a toponym (the name of a village, river, etc), and there is no way to determine without much further work (and sometimes even with much further work) whether it should be classified as a language or as a dialect.
- Hudson, Alfred B. 1976. The Barito isolects of Borneo. (Southeast Asia Program, Department of Asian Studies, Data Paper no. 68.) Ithaca: Cornell University.