The conventional wisdom has it that a complementizer should occupy a clause-peripheral position, either on the left or the right edge. Ostensibly, this is the only option compatible with multiple spellout approaches to derivation: For a constituent to be labeled as CP, the fragment of structure needs to have C merged at the top.
However, languages are attested where complementizers may occur clause-internally, at least under some conditions. One way to account for these data is to assume that the pre-complementizer material gets topicalized, Danckaert (2012). For instance, in colloquial Russian, any constituent (and probably any number of constituents) may be topicalized past a complementizer, but such a word order will be fairly marked. In some languages the situation appears to be more complex: complementizers may appear either anywhere between the left edge of the clause and the verb (Georgian, Ossetic), or strictly preverbally, (Ossetic). Furthermore, wh-words are obligatorily preverbal in these languages.
In my talk, I will discuss theoretical options for analysis of these phenomena, concentrating on Ossetic data. I argue that, in order to account for data of this type, one has to allow movement to proceed within a closed phase. I propose that in the narrow syntax C indeed occupies the highest position in the clause, and wh-phrases move into its specifiers. I will compare the potential of two competing accounts for preverbal complementizers: (a) that C0 with its specifiers is lowered towards the verbs, and (b) that the material between the verb and C forms a single prosodic constituent that includes the topic, and undergoes pied-piping. The movement is driven by the need of the topic to get a specific prosodic contour, cf the account of Zubizarreta (1998) for prosodically driven focus fronting, or the approach of Richards (2010) to licensing of wh-movement.
Danckaert, Livien. 2012. Latin Embedded Clauses. The Left Periphery. Amsterdam: Benjamins.
Richards, Norvin. 2010. Uttering Trees. Cambridge, Ma: The MIT Press.
Zubizarreta, Maria Luisa. 1998. Prosody, Focus, and Word Order. Cambridge, Ma: MIT Press