Do ‘say’ verbs really grammaticalize into complementizers through clause combination?

When a ‘say’ clause is combined with a quoted-speech clause, one of two hypothetical pathways may be followed: (a) a complementation pathway on which the ‘say’ clause takes the quoted-speech clause as its complement clause and thus becomes its matrix clause; (b) a conjoining pathway which involves no syntactic operation but rather the loss of a prosodic gap between the two. Following the second pathway, ‘say’ may become grammaticalized into a quotative particle. On neither pathway is ‘say’ grammaticalized into a complementizer. It is proposed that cross-linguistically so-called ‘say’ complementizers, including the alleged Chinese complementizer shuō, are more likely to be not complementizers but rather quotative particles.