Learn Turkish: Buzdolabı açık mı? - Is the refrigerator open?

Buzdolabı is a compound noun built from two words: buz (ice) and dolap (cupboard). In Turkish, when you combine two nouns like this to make a new specific concept (an "ice cupboard"), the second word must take a compound suffix. Here, that suffix is -ı.

Why does dolap change to dolab- inside this word?

This happens because of a rule called consonant mutation. When you add a suffix starting with a vowel (like the -ı we just added) to a word ending in p, ç, t, or k, that final letter softens to make it easier to pronounce. The hard p in dolap turns into a soft b.

Where is the word "is" in this sentence?

Turkish doesn't have a direct equivalent for the English verb "to be" (am/is/are) in simple descriptive sentences like this. Simply placing the subject (buzdolabı), the descriptive word (açık), and the question particle (mı) in order is all you need to say "Is the refrigerator open?".

Why did we use mı for the question word instead of mi or mu?

The yes/no question particle changes its vowel to match the word right before it, following the 4-way vowel harmony rule. Because the last vowel in açık is an ı, the particle takes the matching vowel and becomes mı.