Learn Turkish: Kedi artık sakin mi?

The word artık actually marks a change in state. In negative sentences, it translates perfectly to "anymore" (e.g., I don't do that anymore). However, in positive sentences and questions like this one, it indicates that a new state has begun. Therefore, it translates better to "now" or "from now on," implying the cat was previously agitated but has now become calm.

What is the difference between using artık and şimdi (now) in this sentence?

If you asked Kedi şimdi sakin mi?, you are simply asking about the current moment in time ("Is the cat calm right now?"). By using artık instead, you are specifically highlighting a shift in behavior or expectations, making it mean something closer to "Has the cat finally calmed down?"

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

Yes! Adverbs of time and phase are quite flexible in Turkish. You could say Artık kedi sakin mi? and it would be perfectly understood. Placing artık right before sakin just groups it a bit closer to the adjective, emphasizing the change into that specific calm state.

Where is the verb "is" in this sentence?

In the Turkish present tense, the third-person "to be" suffix (such as -dir) is very frequently dropped in everyday speech. Sakin is the adjective meaning "calm." By simply placing the yes/no question particle mi after the adjective, Kedi ... sakin mi? fully captures "Is the cat ... calm?" without needing a literal verb.