Learn Turkish: Sen koleksiyoncusun, değil mi? - You are a collector, aren't you?

When used as a confirmation tag ("aren't you?", "isn't it?", etc.), değil mi is invariable. This means it never changes or takes personal suffixes, no matter who the sentence is about. The personal suffix (-sun) stays on the main word (koleksiyoncusun).

What is the difference between Sen koleksiyoncusun, değil mi? and Sen koleksiyoncu değil misin??

The first one uses a tag question to seek confirmation: "You are a collector, right?". You expect they will say yes. The second one is a standard negative question: "Aren't you a collector?" and attaches the personal suffix directly to the question particle (misin).

How does the suffix on koleksiyoncu work?

The root is koleksiyon (collection). The suffix -cu (which follows 4-way vowel harmony) is used to indicate a person's profession, habit, or characteristic. So, a koleksiyoncu is someone who makes or keeps collections.

Can I drop the word Sen from this sentence?

Yes, you can simply say Koleksiyoncusun, değil mi?. The personal suffix -sun on the noun already makes it completely clear that you are saying "you are". Including Sen just adds a little extra emphasis to the "you".