ISO 639-1 Cheatsheet - Language Code Reference
Localization breaks silently when the language you detect doesn't match the one you ship. Grouped by region, each two-letter code pairs its English and native name so you pick without confusing zh/zh-CN or pt/pt-BR. Use it to set the lang attribute, build Accept-Language negotiation, and store a canonical locale key. After reading you assign locale codes that browsers and backends agree on.
Asian Languages 12
zh中文 Chinese
zh-CN简体中文（中国大陆）
zh-TW繁体中文（台湾）
zh-HK繁体中文（香港）
ja日语 Japanese
ko韩语 Korean
vi越南语 Vietnamese
th泰语 Thai
id印尼语 Indonesian
ms马来语 Malay
hi印地语 Hindi
bn孟加拉语 Bengali
European Languages 22
en英语 English
en-US英语（美国）
en-GB英语（英国）
fr法语 French
de德语 German
es西班牙语 Spanish
it意大利语 Italian
pt葡萄牙语 Portuguese
pt-BR葡萄牙语（巴西）
ru俄语 Russian
pl波兰语 Polish
nl荷兰语 Dutch
sv瑞典语 Swedish
da丹麦语 Danish
no挪威语 Norwegian
fi芬兰语 Finnish
el希腊语 Greek
tr土耳其语 Turkish
cs捷克语 Czech
hu匈牙利语 Hungarian
ro罗马尼亚语 Romanian
uk乌克兰语 Ukrainian
Middle East & African Languages 5
ar阿拉伯语 Arabic
he希伯来语 Hebrew
fa波斯语 Persian
sw斯瓦希里语 Swahili
af南非语 Afrikaans
Other Languages 2
la拉丁语 Latin
eo世界语 Esperanto
HTTP Accept-Language Example 4
Accept-Language: zh-CN,zh;q=0.9优先简体中文
Accept-Language: en-US,en;q=0.9优先美式英语
Accept-Language: ja,en;q=0.8优先日语，备选英语
Accept-Language: *接受任何语言
HTML lang 4
<html lang="zh-CN">简体中文页面
<html lang="zh-TW">繁体中文页面
<html lang="en">英语页面
<html lang="ja">日语页面
Tips
- ISO 639-1 is two-letter codes; ISO 639-2 is three-letter (more detailed).
- Language tags can carry a region suffix, e.g. zh-CN (Simplified), zh-TW (Traditional).
- The Accept-Language request header negotiates content language; the server returns the matching version.
- The HTML lang attribute helps search engines and screen readers detect language.
- i18n libraries (i18next, vue-i18n) use these codes as locale identifiers.
Official References
Each command links to its official documentation below, so you can verify the latest usage and read deeper.
Maintained by LaoHand
Publicly updated on Jul 21, 2026, continuously proofread against official docs.
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