The terms “bilingual” and “bilingualism” are understood here in the meaning usedby E. HAUGEN , Bilingualism in the Americas, Alabama 1956, p.9: “Bilinguals (...) is a cover term for people with a number of different language skills, having in common only that they are not monolinguals”. Cf. also the same author, The Norwegian language in America, Philadelphia 1953, p.7: “Bilingualism is understood here to begin at the point where the speaker of one language can produce complete meaningful utterances in the other language”.
, Structure formelle des textes et communications, Word, 10 (1954) pp.1–42 and G. Herdan , The Calculus of Linguistic Observations, Mouton & Co, The Hague 1962, pp.59–64.