Learn Turkish: Öğrencinin bir sorusu var. - The student has a question.

In Turkish, the genitive (possessive) suffix is -in, -ın, -ün, or -un. However, when a word ends in a vowel, like öğrenci (student), you must add a buffer letter n before the suffix to separate the two vowels. So, öğrenci + n + in becomes öğrencinin (the student's).

How does Turkish express 'having' something in this sentence?

Turkish doesn't have a direct verb for 'to have'. Instead, it uses a possessive structure combined with the word var (there is / exists). Literally, this sentence translates to 'The student's (öğrencinin) a question of theirs (sorusu) exists (var).'

What is the -su at the end of sorusu?

It is the 3rd-person possessive suffix. When you use the genitive case to say someone owns something (like öğrencinin), the thing they own must also get a possessive suffix. The word for question is soru. Because it ends in a vowel, it takes the buffer letter s, followed by the suffix u (matching vowel harmony), becoming sorusu (his/her/its question).

Could I put bir at the very beginning of the sentence?