Learn Turkish: Onlar tatile gidiyor. - They are going on holiday.

Nereye asks "where to?". When answering, the destination needs the direction suffix -e or -a. The word for holiday is tatil. Since its last vowel is an "i", we add -e to make tatile.

Why does "tatile" mean "on holiday" instead of "to holiday"?

In English, we say we go "on" holiday. However, Turkish treats a holiday as a destination you travel towards. Therefore, it uses the "to" direction suffix -e on the word tatil.

The dictionary says the verb to go is "gitmek". Why is it spelled "gidiyor" here?

This is because of consonant softening. The root of the verb is git-. When a suffix starting with a vowel is added (like the present continuous -iyor), the hard t at the end changes to a softer d to make pronunciation smoother.

Why is the verb "gidiyor" instead of the plural "gidiyorlar" when the subject is "Onlar"?

In Turkish, if you already include the plural pronoun Onlar in the sentence, it is optional to add the plural suffix -lar to the verb. You can correctly say either Onlar tatile gidiyor or Onlar tatile gidiyorlar.