Player Language is one of the factors which decides where a player plays.
So who decided what language should a player from each nationality have? Or were they off wiki/google?
Some of the language nationality pairings seem a bit "weird"

There are a lot of countries, some may be wrong. We can fix that if you point them out.

We don't use all the small languages though. Some similar languages may be grouped under the same name.

Personally I would like it if some countries support more than one language. For instance Swiserland now always gives French. There are more languages spoken there:
63% = German
20% = French
7% = Italian

I would like it if 63% of the new Swiss players would speak German, 20% French and 7% Italian. But I can imagine that creating problems in the software. If there is 1 language for Switserland German would be more accurate then French.
http://en.wikipedia.org/wiki/Languages_of_Switzerland

Can a player speaks more then 1 language?

seems to me that when a player has been in other country for long time he would learn the language...

The pairings are not necessarily incorrect but Pakistan- English looks weird when Hong Kong is paired with Chinese.
And then there is Bhutan - Nepali.

Not that it matters but its just that if language is a factor(may not be a big one) in determining which team a player chooses, clubs in a lot of nations will have to say "bring me your tired your weary.... " and accept a bunch of English,French,Arabic speaking towel hangers/scrubs just so that they ll be on even keel.

Most of people in Singapore speak Chinese.

A lot of countries do have a second language in the game and it's also used for some background stuff, the transfer market only uses the first language now though.

Singapore does have chinese for example. Wikipedia says about Singapore:
"English is the common language of the nation and is the language of business, government and medium of instruction in schools"
Which is why I made english first language and chinese second.

I've changed switzerland to german, with french as second.

As for pakistan, english seems to be an official language there? When there's a choice between languages I favored the ones that were also spoken in other countries. The way the languages are used this is better for both the players and managers from these countries.

Bhutan I'm afraid I didn't give much thought other than that I want to avoid languages spoken only in one small country.

@Vincent Did you have to do that for all existing Swiss players? Now you have completely messed up my balance in languages of my players... :P

(sorry, it's fun to complain so I couldn't stop myself...)