Repertoires
A repertoire is the set of linguistic resources available to a person or community. Individuals can read a language they rarely speak, recognize formal phrases they cannot freely compose, or command different varieties in different settings. “Bilingual” is therefore not a uniform level of mastery. Record what the source demonstrates: a translated document, an alternation within a text, a school exercise or an interview. Do not infer that all members of a region shared the writer’s repertoire.
UNESCO’s vitality framework treats domains of use and intergenerational transmission as separate dimensions. A non-dominant language may remain strong in family communication while a dominant language occupies education and government. The reverse configuration is also possible for a learned language: a written or religious role may persist after family transmission ceases. Neither literacy nor official recognition alone measures everyday speaking.
Institutions and households
An archive may be multilingual because its scribes served several audiences. A temple, court or school may preserve a prestigious older variety even when neighboring households use something else. In Mesopotamia, the Digital Corpus of Cuneiform Lexical Texts documents Sumerian–Akkadian lexical lists as a teaching and scholarly tradition. Its account also notes later Aramaic and Greek communication; the continued copying of Sumerian lists tells us about education and scholarship, not the mother tongue of every person who handled a tablet.
Vietnam provides another distinction. A Library of Congress country study describes Chinese as a language of officialdom and scholarship while Vietnamese continued as a popular language; chữ Nôm supported written Vietnamese literature. This is not a simple story of a single language replacing another. The relation among literary prestige, spoken continuity and script choice has to be described domain by domain.
A specialized domain
UNESCO describes Machaj Juyai-Kallawaya among Bolivian healers as a threatened knowledge-bearing language maintained in kinship groups while Quechua serves much daily social life in the region. This modern documented case is a comparison, not an ancient-language claim. It shows why counting public signage or schoolbooks would miss a specialized speech domain, and why a language’s restricted use does not make it culturally marginal to the people who preserve it.
Practice: draw a domain table with rows for home, trade, school, administration, ritual and literature. For each row, write the actual evidence and an uncertainty mark, not a guessed language. If a source only establishes a court’s written practice, leave home speech unfilled. A blank cell makes the inference boundary visible.
Modern-language examples on this page clarify a linguistic pattern. They do not establish unattested sounds or forms for an ancient language. Follow the cited sources below and keep editorial readings separate from the surviving trace.