For example, Arabic has a ternary number system: singular, dual, and plural. If a bilingual speaker uses an English phrase as a subject that would have dual number in Arabic (but of course the distinction doesn't exist in English), does the Arabic verb take the dual or plural form? Or is this blocked because of the mismatch?
My instincts tell me it would take dual number, but I'm not sure. What is the theoretical account for this?