The srclang attribute specifies the language code of the track text data. Not to be confused with Country code. The language code tells the browser what kind of characters to expect. This attribute is required if kind="subtitles", not when set to kind="captions".
Language code list reference for subtitle tracks in html5:
| Language | ISO Code |
|---|---|
| Abkhazian | ab |
| Afar | aa |
| Afrikaans | af |
| Akan | ak |
| Albanian | sq |
| Amharic | am |
| Arabic | ar |
| Aragonese | an |
| Armenian | hy |
| Assamese | as |
| Avaric | av |
| Avestan | ae |
| Aymara | ay |
| Azerbaijani | az |
| Bambara | bm |
| Bashkir | ba |
| Basque | eu |
| Belarusian | be |
| Bengali (Bangla) | bn |
| Bihari | bh |
| Bislama | bi |
| Bosnian | bs |
| Breton | br |
| Bulgarian | bg |
| Burmese | my |
| Catalan | ca |
| Chamorro | ch |
| Chechen | ce |
| Chichewa, Chewa, Nyanja | ny |
| Chinese | zh |
| Chinese (Simplified) | zh-Hans |
| Chinese (Traditional) | zh-Hant |
| Chuvash | cv |
| Cornish | kw |
| Corsican | co |
| Cree | cr |
| Croatian | hr |
| Czech | cs |
| Danish | da |
| Divehi, Dhivehi, Maldivian | dv |
| Dutch | nl |
| Dzongkha | dz |
| English | en |
| Esperanto | eo |
| Estonian | et |
| Ewe | ee |
| Faroese | fo |
| Fijian | fj |
| Finnish | fi |
| French | fr |
| Fula, Fulah, Pulaar, Pular | ff |
| Galician | gl |
| Gaelic (Scottish) | gd |
| Gaelic (Manx) | gv |
| Georgian | ka |
| German | de |
| Greek | el |
| Greenlandic | kl |
| Guarani | gn |
| Gujarati | gu |
| Haitian Creole | ht |
| Hausa | ha |
| Hebrew | he |
| Herero | hz |
| Hindi | hi |
| Hiri Motu | ho |
| Hungarian | hu |
| Icelandic | is |
| Ido | io |
| Igbo | ig |
| Indonesian | id, in |
| Interlingua | ia |
| Interlingue | ie |
| Inuktitut | iu |
| Inupiak | ik |
| Irish | ga |
| Italian | it |
| Japanese | ja |
| Javanese | jv |
| Kalaallisut, Greenlandic | kl |
| Kannada | kn |
| Kanuri | kr |
| Kashmiri | ks |
| Kazakh | kk |
| Khmer | km |
| Kikuyu | ki |
| Kinyarwanda (Rwanda) | rw |
| Kirundi | rn |
| Kyrgyz | ky |
| Komi | kv |
| Kongo | kg |
| Korean | ko |
| Kurdish | ku |
| Kwanyama | kj |
| Lao | lo |
| Latin | la |
| Latvian (Lettish) | lv |
| Limburgish ( Limburger) | li |
| Lingala | ln |
| Lithuanian | lt |
| Luga-Katanga | lu |
| Luganda, Ganda | lg |
| Luxembourgish | lb |
| Manx | gv |
| Macedonian | mk |
| Malagasy | mg |
| Malay | ms |
| Malayalam | ml |
| Maltese | mt |
| Maori | mi |
| Marathi | mr |
| Marshallese | mh |
| Moldavian | mo |
| Mongolian | mn |
| Nauru | na |
| Navajo | nv |
| Ndonga | ng |
| Northern Ndebele | nd |
| Nepali | ne |
| Norwegian | no |
| Norwegian bokmål | nb |
| Norwegian nynorsk | nn |
| Nuosu | ii |
| Occitan | oc |
| Ojibwe | oj |
| Old Church Slavonic, Old Bulgarian | cu |
| Oriya | or |
| Oromo (Afaan Oromo) | om |
| Ossetian | os |
| Pāli | pi |
| Pashto, Pushto | ps |
| Persian (Farsi) | fa |
| Polish | pl |
| Portuguese | pt |
| Punjabi (Eastern) | pa |
| Quechua | qu |
| Romansh | rm |
| Romanian | ro |
| Russian | ru |
| Sami | se |
| Samoan | sm |
| Sango | sg |
| Sanskrit | sa |
| Serbian | sr |
| Serbo-Croatian | sh |
| Sesotho | st |
| Setswana | tn |
| Shona | sn |
| Sichuan Yi | ii |
| Sindhi | sd |
| Sinhalese | si |
| Siswati | ss |
| Slovak | sk |
| Slovenian | sl |
| Somali | so |
| Southern Ndebele | nr |
| Spanish | es |
| Sundanese | su |
| Swahili (Kiswahili) | sw |
| Swati | ss |
| Swedish | sv |
| Tagalog | tl |
| Tahitian | ty |
| Tajik | tg |
| Tamil | ta |
| Tatar | tt |
| Telugu | te |
| Thai | th |
| Tibetan | bo |
| Tigrinya | ti |
| Tonga | to |
| Tsonga | ts |
| Turkish | tr |
| Turkmen | tk |
| Twi | tw |
| Uyghur | ug |
| Ukrainian | uk |
| Urdu | ur |
| Uzbek | uz |
| Venda | ve |
| Vietnamese | vi |
| Volapük | vo |
| Wallon | wa |
| Welsh | cy |
| Wolof | wo |
| Western Frisian | fy |
| Xhosa | xh |
| Yiddish | yi, ji |
| Yoruba | yo |
| Zhuang, Chuang | za |
| Zulu | zu |
Original source: https://www.w3schools.com/TAgs/ref_language_codes.asp
