Learn Turkish: Arabasını tamir ettirenler otobüse biniyor. - Those who have their car repaired are getting on the bus.

Tamir etmek means "to repair." By adding the causative suffix -tir to the helper verb et-, we get tamir ettirmek, which means "to have (something) repaired" or "to make (someone) repair (something)." Because the root et- ends in a voiceless consonant (t) and has an 'e' as its vowel, the suffix takes the form -tir according to vowel harmony and consonant mutation rules.

How does ettirenler translate to "those who have (it) repaired"?

This word combines the causative verb ettir- with the subject participle -en ("the one who..."). Normally, this would describe a noun, like tamir ettiren insanlar (people who have it repaired). However, Turkish frequently drops the noun and attaches the plural suffix -ler directly to the participle. So, ettirenler stands alone to mean "those who have (it) done."

Why does arabasını have two similar-looking vowel endings?

The word breaks down into root + possessive + accusative. First, araba-sı means "his/her/their car" using the possessive suffix. Because this specific car is the direct object of the repair, it needs the accusative case. When adding a case ending to a possessive suffix, Turkish requires the buffer letter -n-, followed by the accusative suffix -ı, resulting in arabasını.

Why is "on the bus" translated with the dative case as ?