Learn Turkish: Hâkim farklı bir hüküm vermeliydi çünkü kanıt sahteydi. - The judge should have given a different verdict because the evidence was fake.

It combines the necessity suffix -meli (must/should) with the past tense suffix -di. Together with the buffer -y-, ver-meli-y-di literally means "was in a state of having to give". In Turkish, this combination expresses an unfulfilled past obligation, which translates perfectly to "should have given".

Why is the word order farklı bir hüküm instead of bir farklı hüküm?

In Turkish, when you have an adjective (like farklı) and the indefinite article bir (a/an), the adjective almost always comes before bir. The pattern is "adjective + bir + noun", unlike English which uses "a + adjective + noun".

Why do both vermeliydi and sahteydi have a -y- before the past tense suffix?

The past tense suffix here is actually the past copula idi (meaning "was") attaching to the previous word. When it attaches to a word ending in a vowel, like vermeli or sahte, the i in idi drops and is replaced by the buffer letter -y- to connect the vowels smoothly.

I noticed the word is hüküm. Does it change if we add a vowel suffix to it?