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.