How long you been seeing her?

[Mary Bright]

I was watching a film the other day and came across the following phrase:
A man is secretly going out with a woman. When his friend finds out about the fact, he asks him, ' How long you been seeing her?'
As far as I understand, here is the Present Perfect Continuous, but 'have' is obviously missing and there's a usual word-order in a question-sentence. So, is it a form of Present Perfect Cont. typical of colloquial speech? Would be interesting to know.
Thanks a lot

[billmcd]

I was watching a film the other day and came across the following phrase:
A man is secretly going out with a woman. When his friend finds out about the fact, he asks him, ' How long you been seeing her?'
As far as I understand, here is the Present Perfect Continuous, but 'have' is obviously missing and there's a usual word-order in a question-sentence. So, is it a form of Present Perfect Cont. typical of colloquial speech? Would be interesting to know.
Thanks a lot

Yes, you have termed it very nicely. It is 'typical of colloquial speech' and the statement/question should include "have".

[Tdol]

You will come across this in colloquial British English too.