What is the -tür suffix again?
It is a version of "-dir" with vowel harmony and consonant hardening.
Full info here: https://forum.duolingo.com/comment/8649151
Is it natural to say "Bariş'ın annesi Türk, benim annem Alman" ?
Why "Türktür" is not accepted?
'benim ise alman' olmaaaaz mıııı?
You can say "Benimki ise".
benimkisi alman neden kabul değil
It definitely isn't the best answer, but it isn't wrong I suppose. Just keep in mind that what we have above is the most natural sounding one :)