>>>It's the same in English- the indefinite article a becomes an before a word starting with a vowel.
>>>
>>> For u it depends how it is pronounced - I think
>>>
>>>A U-Turn
>>>An unrelated matter
>>
>>On a related note, same goes for words beginning with an aitch - "an honorable exception".
>>
>>Btw, a question for the anglophone majority here: is there a word in English which begins with a "u" and has it pronounced as u? Not as uh as in under, not as yoo as in universe, but as u as in butcher, lubricate?
>
>I thought 'U' was pronounced as in 'u' of Universe ?

Just like Metin, I distinctly hear it as yunivers (or junivers/јуниверс in Serbian phonetics).

And that's not what I was looking for. It's the few rare occasions when u is pronounced as yu without the y, i.e. like in butcher, pudding.

Can't really use English to spell this out, because there are several ways to pronounce a single u (i.e. without pairings like ou, au, ue, ur) - there's the uh, as in umbrella, upsize, numb, then the yoo as in use, union, unicorn, and this u as u as in butcher, pudding, cushion (not everywhere!). I think there was a fourth way in some words, but can't remember it.