tstlai supports a wide range of languages, categorized by translation proficiency tier (based on AI model capabilities).
Tier 1: High Proficiency#
These languages have the highest quality of translation and nuance preservation.
| Code | Language | Region |
|---|---|---|
en_US | English | United States |
en_GB | English | United Kingdom |
de_DE | German | Germany |
es_ES | Spanish | Spain |
es_MX | Spanish | Mexico |
fr_FR | French | France |
it_IT | Italian | Italy |
ja_JP | Japanese | Japan |
pt_BR | Portuguese | Brazil |
pt_PT | Portuguese | Portugal |
zh_CN | Chinese | Simplified |
zh_TW | Chinese | Traditional |
Tier 2: Good Proficiency#
Translations are accurate and grammatically correct, suitable for production use.
| Code | Language | Region |
|---|---|---|
ar_SA | Arabic | Saudi Arabia (RTL) |
bn_BD | Bengali | Bangladesh |
cs_CZ | Czech | Czech Republic |
da_DK | Danish | Denmark |
el_GR | Greek | Greece |
fi_FI | Finnish | Finland |
he_IL | Hebrew | Israel (RTL) |
hi_IN | Hindi | India |
hu_HU | Hungarian | Hungary |
id_ID | Indonesian | Indonesia |
ko_KR | Korean | South Korea |
nl_NL | Dutch | Netherlands |
nb_NO | Norwegian | Norway |
pl_PL | Polish | Poland |
ro_RO | Romanian | Romania |
ru_RU | Russian | Russia |
sv_SE | Swedish | Sweden |
th_TH | Thai | Thailand |
tr_TR | Turkish | Turkey |
uk_UA | Ukrainian | Ukraine |
vi_VN | Vietnamese | Vietnam |
Tier 3: Functional Proficiency#
Translations are understandable but may lack idiomatic nuance.
| Code | Language | Region |
|---|---|---|
bg_BG | Bulgarian | Bulgaria |
ca_ES | Catalan | Spain |
fa_IR | Persian | Iran (RTL) |
hr_HR | Croatian | Croatia |
lt_LT | Lithuanian | Lithuania |
lv_LV | Latvian | Latvia |
ms_MY | Malay | Malaysia |
sk_SK | Slovak | Slovakia |
sl_SI | Slovenian | Slovenia |
sr_RS | Serbian | Serbia |
sw_KE | Swahili | Kenya |
tl_PH | Tagalog | Philippines |
ur_PK | Urdu | Pakistan (RTL) |
Fallback Codes#
You can also use 2-letter ISO codes, which default to the standard dialect.
en→ Englishes→ Spanishfr→ Frenchde→ Germanit→ Italianpt→ Portuguesezh→ Chineseja→ Japaneseru→ Russianko→ Korean
Right-to-Left (RTL) Support#
tstlai automatically detects RTL languages and sets the dir="rtl" attribute on the <html> tag for:
- Arabic (
ar) - Hebrew (
he) - Persian (
fa) - Urdu (
ur) - Pashto (
ps) - Sindhi (
sd) - Uyghur (
ug)