Learn Turkish: Traktörde küreğin var mı? - Do you have a shovel in the tractor?

To say you have a shovel, Turkish literally says your shovel exists. The suffix -in is the possessive ending for your. When a vowel-starting suffix is added to a word ending in k, the k almost always softens into a ğ (soft g) due to consonant mutation.

Why do we use var mı instead of a verb for do you have?

Turkish does not have a direct verb for to have. Instead, you use the possessive ending on the object (like küreğin for your shovel) followed by var (exists) or yok (does not exist). Adding the question particle mı turns it into does your shovel exist?

Why does traktör take the suffix -de rather than -da?

The suffix must follow two-way vowel harmony. The last vowel in traktör is ö, which is a front vowel. Front vowels take suffixes with e, making the locative (in/on/at) suffix -de.

I don't see the -mAdIkçA (unless/as long as) suffix from this lesson here. How would we apply it to this sentence?