Learn Turkish: Kar birikmekle kalmayıp yolları kapladı. - The snow not merely accumulated, but covered the roads.

This is a fixed structure meaning "not only... but also...". It combines the infinitive birikmek (to accumulate) with the instrumental suffix -le (with), followed by kalmayıp (not staying/stopping). Literally, it means "The snow did not stop with accumulating, and..." which translates smoothly to "not merely accumulated, but...".

Why is the suffix -(y)ıp used in kalmayıp instead of a regular past tense like kalmadı?

The suffix -(y)ıp is a connecting converb that links two actions done by the same subject, acting like "and". By using kalmayıp instead of kalmadı ve, the sentence flows much more naturally and ties the two consecutive actions tightly together.

Does kalmayıp need to show tense or who is doing the action?

No. A major feature of the -(y)ıp suffix is that it is timeless and personless on its own; it borrows the tense and subject from the final verb in the sentence. Here, kalmayıp gets its meaning of "it did not just..." from the past tense third-person ending on the main verb kapladı (it covered).

Why is the word for roads written as yolları instead of just yollar?