Learn Turkish: Baba araba yıkıyor mu? - Is the father washing a car?

mu is the question particle that turns a statement into a yes/no question. It is always written as a separate word, but its vowel changes to follow the rules of vowel harmony based on the word right before it. Since the last vowel in yıkıyor is o, the particle becomes mu.

The root for 'to wash' is yıka-. Why is it spelled yıkıyor instead of yıkayor?

When a verb root ends in the wide vowels a or e (like yıka-), that vowel is dropped or narrowed to match the present continuous ending (-iyor, -ıyor, etc.). Here, the a in yıka- changes to ı, giving us yıkıyor.

Why aren't there words for 'the' and 'a' in the Turkish sentence?

Turkish doesn't have a definite article like 'the', so baba can mean 'father' or 'the father' depending on context. For 'a car', you could say bir araba, but when talking about a general everyday activity (like 'car washing'), Turkish often leaves out bir entirely.

How does the word order work in this question?