In this paper, I have shown that Joshi's (1982) framework of codeswitching constraints can largely be applied to Swedish-English code-switches. I feel qualified to conclude that Joshi's claims concerning the non-switchability of closed class items and matrix language and embedded languages are held up by the Swedish- English data. The need for corresponding categories proved to be less clear-cut than originally proposed by Woolford (1983) and others. It seems that optimal switching conditions are given if the categories, rules and metarules correspond in the two languages. Apparently, however, it is also possible to switch if the node admissibility conditions for the matrix language only are met, as was shown by code-switched sentences containing RPs. This requires that the speaker has a clear sense of which language is the host and which is embedded. Rules from the embedded language only are not acceptable. This calls for some sort of determination strategy by the parser. I found no evidence for determining Lm at any specific point in the sentence, except at the topmost S. Rather, the judgments by code-switchers that a sentence “comes from” one language seems to coincide with the fact that the resulting sentence is based on the rules from that language. Other than that, the matrix language is determined by the communicative context as a whole.The data involving RPs also seemed to indicate that RPs are not separate ategories, but are NPs, introduced by a “de-slashing” rule (Sells 1984). If they were separate categories, this would be evidence for there being no need for category equivalence. In this case, we would have to explicitly state all other cases which require category equivalence (the majority of cases), which is undesirable.
Viscosity solutions for a system of PDEs and optimal switching
