Currently the following icons are used for PT.SO and RU.SO:
In case they are changed, here is what they are as of posting this:
And what they became later:
Portuguese is green, Russian is blue. What these colors are supposed to mean? Random colors from the flags of the corresponding countries?
I suggest using language codes instead: PT and RU. These symbols are easy to add even to the tiniest 16x16 px icons:
If the characters are easy to recognize even on 16x16 px icons, there won't be any issues with bigger icons either.