Gaming@NINA

does (e) mean european and (u) usa or does (e) mean english?

Those are the languages of the rom, all of the above which we can read. (j) is japanese, (b) is bad rom dump, (g) german, (s) spanish, (f) french. I hope i got the last two right.

They aren't necessarily languages, flashbang. They stand for the countries they were released in primarly, then languages (which can also be countries).

(U) = USA\Canada\North America <-Usually just English
(E) = Europe <- often in multiple languages like French, Spanish, Italin, German, etc.
(J) = Japan <-Japanese
(I) = Italy <-Italian
(F) = France\Quebec(French Canadian) <-French
(S) = Spain <-Spanish
(C) = China <-Chinese
You get the idea.
There are two odd ones that aren't used often:
(pd) = Public Domain\homebrew
(x) = Not official release

When things are in square brackets like this [], they mean something else.

[b] = bad dump
[b1], [b2], [bn] = Beta #n
[!] = real dump, etc.

These aren't used as often but you will find them in some places.

(U) is the one I normally download Never even seen the rest (apart from (J) and (E) )