Learn Turkish: Mezuniyetten beri hiç buluşmadık. - We haven't met at all since graduation.

To say 'since' a certain point in time, Turkish uses the ablative case (meaning 'from') attached to the noun, followed by the word beri. Here, mezuniyet (graduation) gets the ablative ending. It becomes -ten instead of -den because mezuniyet ends in a voiceless consonant (t), which changes the suffix through consonant harmony.

Why is the simple past tense verb buluşmadık translated as 'haven't met' instead of 'didn't meet'?

Turkish doesn't have a direct equivalent to the English present perfect tense ('have met'). The Turkish simple past tense, seen here with the -dı ending, is often used for events that happened (or didn't happen) in the past but are still connected to the present. Because of the word 'since', 'haven't met' is the most natural English translation.

What does the word hiç add to this sentence?

The word hiç adds emphasis. By itself, it means 'ever' or 'at all,' but when it is paired with a negative verb like buluşmadık, the whole phrase translates to 'never' or 'not at all'.

How exactly is the verb buluşmadık built?

It is made of four parts: the verb root buluş (to meet or get together), the negative suffix -ma (not), the past tense suffix -dı, and the personal ending -k for 'we'.