Double complementizers

Unlike English, the Mainland Scandinavian languages have a complementizer som in embedded questions with a subject gap; see the Swedish example in (1a) (and cf. Teleman et al. 1999/4: 555 ff.). This is sometimes referred to as "doubly filled comp", following Chomsky & Lasnik (1977). The complementizer is also sometimes marginally possible in wh-clauses without a subject gap; see (1b) and (1c). Teleman et al. (1999/4: 509, 511) refers to the possibility of som 'that' after relative när 'when' or där 'there' as regional in Swedish. Also in Faroese, the relative complementizer ið can sometimes occur after a wh-word, but it is never obligatory (Thráinsson et al. 2004: 303f.). [...