Questions & Answers about Dün dağda kayak yaptık.
Because -da / -de is the locative ending, which means in / on / at.
- dağ = mountain
- dağda = on the mountain / in the mountain area
So dağda tells you the location of the action.
The ending appears as -da, -de, -ta, or -te depending on vowel harmony and consonant voicing. Here it is -da.
There are two things going on:
Vowel harmony
The last vowel in dağ is a, so the ending uses a rather than e.Consonant voicing
Since dağ ends in a voiced sound, the ending uses d rather than t.
So:
- dağ + da → dağda