Thanks for the links, they'll greatly help refresh my memory , but that wasn't what I was referring to - sorry for being unclear. As rusty as my music theory is, it should still be more than sufficient to read (slowly) any standard sheet music (seven years of piano under my belt... Yup! ).
As a side-note, here in France, music theory doesn't use the letters C, D, E, F, G, H, I; we still use the old set of syllables instead: do, re, mi, fa, sol, la, si (and Chinese traditional music only uses 5 notes out of 7). But that isn't the problem either.

When it comes to playing Asian traditional music...
I was more thinking about the difficulties inherent to the reading of, hum... THIS kind of sheet music.

(and I guess we should consider ourselves lucky this one uses standard Arabic digits instead of the traditional ideograms... This is clearly not the least Westerner-friendly sheet-music I've seen . Japanese traditional sheet music is far worse! )