Learn Hardcore Turkish: Otomobil küçük ama kullanışlı.

In Turkish, the present-tense copula is usually omitted. Instead, an adjective placed after a noun serves as the predicate. So Otomobil küçük literally means “Car small” → “The car is small.”

Why are küçük and kullanışlı placed after otomobil instead of before it?

Here they function as predicate adjectives describing otomobil. Predicate adjectives follow the noun. If you want them attributively (“small car,” “practical car”), you put them before: küçük otomobil, kullanışlı otomobil.

What does ama mean and how is it used?

Ama means “but” or “however.” It’s a coordinating conjunction used to join two contrasting clauses. In this sentence it contrasts the car being small with it being practical.

What is the suffix -lı in kullanışlı, and how does it work?

The suffix -lı/-li/-lu/-lü attaches to a noun or verb-noun (like kullanış “use, usability”) to form an adjective meaning “with,” “having,” or “characterized by.”
kullanış + ‑lı → kullanışlı (“useful,” literally “with usability”).

How does vowel harmony determine which form of this suffix to use?