Learn Turkish: Kahvene süt ekleyeyim mi? - Shall I add milk to your coffee?

We start with the verb stem ekle. Since the stem ends in a vowel, we add the buffer letter y. Then we add the 1st person singular optative suffix -eyim (meaning "let me" or "shall I"), giving us ekleyeyim.

Why is the word for coffee written as kahvene here?

Kahvene means "to your coffee." It breaks down into kahve (coffee), plus the 2nd person singular possessive suffix -n (your), and finally the dative case suffix -e (to). The verb eklemek requires this dative case for the destination you are adding something to.

Why doesn't süt (milk) have an accusative case ending like "sütü"?

In Turkish, we only use the accusative case for specific or definite direct objects (like "the milk"). Because we are just talking about adding "milk" in general, it stays in its plain, dictionary form.

How does the question particle mi work with the optative mood in this sentence?

By adding the question particle mi after a 1st person optative verb like ekleyeyim (let me add), the statement turns into an offer or suggestion: "shall I add?". As always, the particle is written as a separate word and its vowel matches the last vowel of the verb.