According to Nortel/Avaya;
The built-in languages supported by the IP Phone 1210 are:
Arabic, Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hebrew, Hungarian, Italian,
Japanese (Katakana only), Latvian, Norwegian, Polish, Portuguese, Russian, Spanish, Swedish, Turkish
The built-in languages supported by the IP Phone 1220 and 1230 are:
Czech, Danish, Dutch, English, Finnish, French, German, Hungarian, Italian,
Japanese (Katakana only), Latvian, Norwegian, Polish, Portuguese, Russian, Spanish, Swedish, Turkish
I've never used anything but English so I couldn't tell you anymore than that.
Good Luck!