Constraints on code-switching: how universal are they?

A welcome development of the past few years has been an awakening of interest among theoretical linguists in the potential of bilingual speech for the theory of language. In so doing, they have unwittingly reopened an issue that has interested researchers into bilingualism in the past (such as Haugen, 1953; 1956; 1973; Hasselmo, 1961; 1974; Gilbert, 1969; Shaffer, 1975; Clyne, 1969; 1971; 1980).