Please. This is seriously starting to become a nuisance.

Some widely heard languages in WoW that aren't on the list could include:
-Norwegian
-Finnish
-Serbian
-Polish
-Danish
-Latvian
-Lithuanian
-Estonian
-Czech
-Slovakian/Slovenian
-Hungarian
-Romanian

There are some of the major European languages I've seen spoken in the World of Warcraft scene. For minor languages, you can always search the internet (for example, Wikipedia offers a list of all countries in Europe, which includes also the languages spoken in the countries: http://en.wikipedia.org/wiki/List_of_sovereign_states_and_dependent_territories_in_Europe )

EDIT: The Wikipedia link also includes flags for each country/spoken language.

More language options

Whenever I'm trying to create a premade for playing 3v3 with my landsmen, I type in "Finnish only". Seemingly many people get confused with this and don't understand that Finnish is a nationality and Finland is a country. Hence, I suggest adding more language options to the language tab - afterall, they're just pixel flags and words after them. If it would be possible, it would be nice to see my own country and why not the rest of the European language pool also. There will always be people who raise a false hope by signing on the list and not understanding that I'm seeking players that speak a language that is not listed in oQueue.