[Nightedge]

Could I put are in the blank?

-Here we have recordings that __ German accent.

To speak strictly, I think in academic writing be (=are) might be a lazy word, but I think in daily conversation people could be using a sentence structure that might not seem logical. Some might think a recording can't be equal to an accent, but I am not sure whether this would be too rash a statement.

[susan53]

You would have to say :

... recordings that are (spoken) in a a German accent
... recordings that are spoken with a German accent
... recordings which use a German accent
etc

They all sound a bit strange though, and suggest to me that it is an actor who has made the recording and that it's not authentic. It's the speaker who has the accent, not the recording. So unless that's what you meant (context again) I'd prefer :

The speakers in these recordings have a German accent.

[Nightedge]

Excellent answer. Thank you.