(Or they're grouped by the untranslated name, even if they're displayed by the translated one, which is what I meant with my first question.)
There are 2 types of translatable strings. One denoting the kind of file - _("%s source file") - _("%s file") - _("%s script") - _("%s document")
and then the actual translation of the language which is inserted inside one of the above 4 strings (i.e. those 5 languages I mentioned above).
The placement into the alphabetic groups is based on the translation of the language, not the translation of the kind of file (which is gone with this patch anyway)