Learn Turkish: Kamyonu sollarken kavşakta kaza yaptı. - He had an accident at the intersection while overtaking the truck.

The suffix -ken means "while". When adding it to a verb, you first put the verb into the Aorist (simple present) tense. Here, the verb sollamak (to overtake) drops the -mak and takes the Aorist suffix -r, becoming sollar. Then we add -ken to make sollarken (while overtaking).

Is the verb sollamak related to the word sol (left)?

Yes! In Turkey, as in most countries driving on the right side of the road, you pass slower vehicles on the left. The verb sollamak was created from the word sol and literally means "to pass on the left".

Why does kamyon have an -u at the end?

It has the accusative case suffix -u because it is the specific direct object of the overtaking action. The driver wasn't just overtaking any random truck, they were overtaking "the" truck.

Why do we say kaza yaptı (made an accident) instead of using a verb for "had"?

In Turkish, you cannot "have" an accident using possessive words like var or sahip olmak. Instead, you always use the helper verb yapmak (to do/make). So, kaza yapmak is the standard phrase for "having an accident".