Interrogative CPsWe know that the complementiser is the head of the CP and that this provides the
relevant features for the force interpretation of the sentence. Some complementisers
are interrogative and some are declarative. Thus, when the clause is interrogative,
presumably it has an interrogative complementiser and vice versa if the clause is
declarative. In yes–no questions, therefore, we might expect the clause to have an
interrogative complementiser. As we can see no complementiser in such sentences, we
must assume it to be abstract. The assumption of such an element is supported by the
fact that in some languages a morpheme with exactly these properties appears overtly.
For example, in Japanese, a yes–no question is marked by the appearance of the
morpheme ka at the end of the clause. Thus, the difference between (43a) and (43b) is
that the first is declarative and the second interrogative:
(43) a Keko-wa sensei desu
Keko teacher is
‘Keko is a teacher’
b Keko-wa sensei desu ka?
‘is Keko a teacher?’
In Japanese, the complementiser goes in the final position of the clause and so the
question particle is suitably analysed as a complementiser. Thus, we might claim that
English is similar to this, the main difference being that the question particle is covert
in English:
(44) CP
C'
C IP
Q she is a teacher?
The simple assumption that this interrogative complementiser is a bound morpheme in
English is enough to justify the movement of the inflectional element to support it:
(45) CP
C'
C IP
is 1 C she t 1 a teacher?
-Q
A similar analysis can be provided for inversion that accompanies wh-movement to
spec CP. As we discussed in the previous section, wh-movement to spec CP
establishes an agreement relationship between the wh-element and the head of CP that