Restrictive vs non-restrictive relative clauses in Hausa where morphosyntax and semantics meet

Restrictive and non-restrictive relative clauses in Hausa are characterized by morpho syntactic properties which are in (near) complementary distribution. Restrictives are introduced by one of two relative markers--either complex HL(L) tone wanda/wadda/waaanda (MSG/FSG/PL) 'the one(s) who(m), which, that etc', or simplex da 'who(m), which, that, etc.'-and (normally) require a focus (suka, suke, etc.) form of the inflectional (perfective/imperfective) agreementaspect paradigms. Non-restrictives, in contrast, are (for many speakers) distinguished from restrictives as follows: (1) they are introduced by a distinctive all L tone allomorph of the explicit relativizing pronoun wanda/wadda/waa anda; and (2) some speakers also allow either the same focus form of the !NFL as occurs in restrictives, or use the neutral non-focus (sun, suna, etc.) form as a possible alternative. This tense-aspect variation is attributable to the fact that non-restrictive relative clauses are (coordinate-like) appositional constructions which do not uniquely restrict/define/identify, etc. their antecedents.