For westerners, *any* language that uses "squiggly lines" instead of the familiar alphabet is going to be doubly hard.

By the time I left South Korea after living there for 4 months, I had the Hangul characters memorized - surprisingly many words were English borrow words.

Japan, on the other hand - Kanji, Hiragana, Katakana, and Romaji... I only really know the ones for the train stops. Shinagawa station - three boxes and three lines. Easy-peasy. Yokohama - a spear, some squiggles, and then a T with a half of a square... The interesting thing is the realization that Tokyo and Kyoto are essentially the same sounds reversed in order but don't use the same kanji.

That's the key, I think. Seeing the foreign words and understanding their literal words in your native language is different from understanding their meanings.

You also run into the issue with some (like me) that have done enough damage to our ears (blown my ear drums about three times now), that any language that has same sound but where you put the emphasis on it make it a different word I will likely never be able to learn, no matter how hard I try, I have a hard time with several English words that are not that close but sound the same to me. Now having said this, I do think this can add a real fun factor to the RPG if you have a good game master.

Что это говорит?
 

That's a good point. All of the game systems that I'm familiar with (admittedly, not a large number) don't differentiate between understanding/speaking a language and being able to read/write and/or understand written language. If the written language uses the same alphabet as the learner's own language, then the skill difference is probably negligible (assuming the user is functional literate in his/her own language) but, as you point out, if the written language is different (different alphabet, ideographs instead of phonograms, etc.), then it's almost an entirely different skill.

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The system I use has scripts and languages as separate skills.

That's probably the way it should be done.

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CORPS gives a discount for a related language as well as for only learning spoken or written (assuming different character set).

I give the PC a "native language" skill equal to either their INT or EDU, whichever is HIGHER.

I allow PCs to roll [the average of INT + CHA] + EDU or less to know a second language as there are many Bi-Lingual families in the US. The primary languages we normally use are:

Spanish
German
Italian
Chinese/Korean
Indian
Native American dialects

but I will allow any language with a suitable backstory. This second language starts at the PC's EDU score in Skill level.