"Ten muž často chodí do matčina bytu."

[EinatAdar]

How do you know that it is my mother and not his mother?

[endless_sleeper]

It's kinda implied.

You would use something like '...do bytu jeho matky.' to stress that it's his mother. Otherwise, I would assume you talk about your own mother.

[Vera13614]

I am czech, i did this for fun. It really doesnt speak about whose mother it is. If you want to emphasize,whose mother it is you say 'do bytu jeho matky' or 'do bytu mojí matky', you have to use the possesive pronoun.

[EinatAdar]

Thanks for the explanation. Is this a general assumption, that the unspecified person is related to the speaker unless it's explicitely stated otherwise?

[endless_sleeper]

I'd say so.

[EinatAdar]

I see. Thanks!