Learn Turkish: Dünkü rüya ve bugünkü gerçek birbirine benzemiyor. - Yesterday's dream and today's reality do not resemble each other.

The suffix -ki usually does not change to follow vowel harmony. However, there are a few exceptions with time words that have rounded vowels, like dün (yesterday) and bugün (today). For these words, the suffix becomes -kü to match the vowel, giving us dünkü and bugünkü.

Could we say dünün rüyası instead of dünkü rüya?

While it might make sense grammatically as a possessive phrase, Turkish strongly prefers using the -ki suffix to turn time words directly into adjectives. Using dünkü directly before rüya is the natural way to express things that happened at a specific time.

Why is there an -ne at the end of birbirine?

The verb benzemek (to resemble) always takes the dative case, meaning you say that something resembles TO another thing. The word birbiri (each other) already contains a possessive ending, so we add the buffer consonant -n- and the dative suffix -e, making it birbirine.

The negative suffix is usually -me or -ma. Why does it look like -mi in benzemiyor?

This happens because of a rule called vowel narrowing. The verb is benzemek and its negative root is benzeme-. When we add the present continuous suffix -iyor, the -y- sound forces the wide -e in the negative suffix to narrow into an -i-, changing it to benzemiyor.