Learn Turkish: Sence bu karar aptalca mı? - In your opinion, is this decision stupid?

The suffix -ce is the equative suffix. When attached to personal pronouns like ben (I) or sen (you), it translates to according to or in the opinion of. Therefore, bence means in my opinion and sence means in your opinion.

Why use aptalca instead of just aptal (stupid)?

While aptal simply means stupid, adding the -ca suffix gives it the feeling of -ish or -like in English. It means something more like foolish or stupid in nature. It is often used to describe the quality of an action, idea, or decision rather than directly calling a person stupid.

Why is the equative suffix -ce on sence but -ca on aptalca?

This happens because of 2-way vowel harmony. The word sen has the front vowel e, so it takes -ce. The word aptal ends with the back vowel a, so it takes the back-vowel version, -ca.

Why is the question particle mı instead of mu?

The question particle must follow 4-way vowel harmony with the word immediately before it. Because the last vowel in aptalca is a, the particle becomes mı. If the preceding word ended in an o or u, it would be mu.