Sort of / kind of / type of are usually followed by an uncountable noun or a singular countable noun with no article, but a / an is sometimes retained in an informal style:
What sort of (a) / kind of (a) / type of (a) dance is that?
Well, it’s a sort of jig or reel, danced to very fast time. I don’t know exactly what it is because there are several types of jigs– single jigs, double jigs, slip jigs and hop jigs.
Note that when the indefinite article is retained, it sometimes has a derogatory meaning:
What kind of a DVD player is that? You don’t seriously expect me to listen to electronic music with no surround sound, do you?
sort of / kind of
Sort of and kind of, but not type of, are used in another important way in informal spoken English when we want to demonstrate to the listener that we are not speaking very precisely but simply indicating a general idea. They are used to modify many different parts of speech including adjectives, verbs and clauses, see below:
Why don’t you like this kind of music? ~ Well, it’s sort of loud and tuneless.
They may also be used as fillers, i.e. to fill a gap in the conversation and to give the speaker more time to think:
How would you describe your singing voice on this track?
Well, I… I kinda howl like a wolf, and then…kinda…kinda…squeal like a pig, but it seems to work, sort of.
from BBC English 🙂