In norway we have the letter “ø” that corresponds to “oe” in english. So in foreign_chars.php, the line:
'/ö|œ/' => 'oe'
'/ö|œ/|ø/' => 'oe'
. And the character Å and å should be “aa” I think.
They're currently present in the sequences for 'o', 'A' and 'a' respectively (in the develop branch). If that's not correct - you should make a pull request to change it.
by the way in Estonian language "ö" shouldn't be transliterated to "oe", it is "o" then. And "ä" as "a" and "ü" as "u". The same in Finnish.
We're talking about a slightly different characters here.
I have to add that Serbian Đ and đ should be transliterated to Dj and dj respectively.
I'm closing this one.
Again - you are free to submit a pull request to add any missing characters. And for those that might be transliterated differently in 2 or more languages we can't really do much. It's a config file, so you can alter it as you wish.