I would like to add some other language descriptions for branded and unbranded firmware:

FS_RUSSIA: EN, RU, EN
FS_JAMAICA: EN, PB, NL, FR, ES, EN
FS_ISRAEL: TL, RU, HE, FR, FA, EN, AZ, AR

FS_VODAFONE_LIVE_A: EN, PT, NL, IT, GL, FR, EU, ES, EN, DE, CA
FS_VODAFONE_LIVE_B: EN, SL, RO, HU, HR, EN, EL, DE, CS, BG
FS_VODAFONE_LIVE_C: EN, TR, IT, IS, FR, FA, EN, DE, AR
FS_T-MOBILE_INTERNATIONAL: EN, TR, SK, PL, NL, MK, HU, HR, EN, DE, CS
FS_TIM_ITALY: EN, IT, FR, EN, DE
FS_TELSTRA: EN, ZS, VI, TL, TH, NL, MS, ID, FR, EN, DE
FS_TELEFONICA: EN, XL, PT, PB, GL, FR, EU, ES, EN, CA
FS_CINGULAR: XL, PB, EN, CF
FS_HUTCHINSON_WORLD: EN, SV, IT, EN, DE, DA
FS_HUTCHINSON_HONG_KONG: EN, ZH, EN
FS_ORANGE_SIGN: EN, XL, SK, RO, PL, NL, GL, FR, EU, ES, EN, DE, CA
FS_ORANGE_CH: EN, IT, FR, EN, DE

I quote also the ones in the sticky thread:

FS_BALTIC: English, Estonian, Latvian, Lithuanian, Russian
FS_HONG_KONG: English, Chinese (Hong Kong)
FS_NORDIC: English, Albanian, Arabic, Croatian, Danish, Finnish, IS, Norwegian, Swedish, Turkish
FS_WESTERN-EUROPE: English, EU, CA, Dutch, French, GL, German, Portuguese, Spanish, Turkish
FS_ADRIATIC: English, Albanian, Bulgarian, Croatian, French, German, Greek, Italian, Romanian, Russian
FS_AMERICA: English, Portuguese, Canadian French, Dutch, French, Latin American Spanish, Spanish
FS_APAC-ANZ: English, Dutch, French, German, Malay, Indonesian-Bahasar, Philippine-Tagalog, Thai, Vietnamese, Chinese simplified
FS_C-ASIA: English, Arabic, AZ, Persian-Farsi, KK, Russian, Turkish, Ukrainian
FS_CENTRAL-EUROPE: English, BS, Croatian, German, Czech, Hungarian, Polish, Serbian, Slovakian, Slovenian
FS_FRANCE: English, French
FS_S-E-EUROPE: English, Albanian, Bulgarian, Croatian, Greek, Hungarian, Macedonian, Romanian, Russian, Serbian
FS_S-ASIA-LEVAN: English, AR, AZ, BN, Persian-Farsi, French, Philippine-Tagalog, Hebrew, Hindi, Russian
FS_S-CENTR-AFR: English, AR, Dutch, Persian-Farsi, HA, German, IG, Sesotho (South Africa), YO, Zulu, Portuguese
FS_TAIWAN: English, Chinese traditional Taiwan