Hungarian has seven short vowels (a, e, i, o, u, ö, ü) including the front unrounded vowels ö and ü. The long equivalents of the first five are written with the acute accent (á, é, í, ó, ú). (The accented a and e is not really just a longer version but articulated differently.)
The double acute acts as combined acute with umlaut, giving the longer version of ö and ü.
|ő||U0151||latin small letter o with double acute|
|ű||U0171||latin small letter u with double acute|
|Ő||U0150||latin capital letter o with double acute|
|Ű||U0170||latin capital letter u with double acute|