| Country | Languages |
| Indonesia | Bahasa Indonesia (official, modified form of Malay), English, Dutch, local dialects (of which the most widely spoken is Javanese) |
| Iran | Persian (official) 53%, Azeri Turkic and Turkic dialects 18%, Kurdish 10%, Gilaki and Mazandarani 7%, Luri 6%, Balochi 2%, Arabic 2%, other 2% (2008 est.) |
| Iraq | Arabic (official), Kurdish (official in Kurdish regions), Turkoman (a Turkish dialect), Assyrian (Neo-Aramaic), Armenian |
| Ireland | English (official, the language generally used), Irish (Gaelic or Gaeilge) (official, spoken mainly in areas along the western coast) |
| Isle of Man | English, Manx Gaelic (about 2% of the population has some knowledge) |
| Israel | Hebrew (official), Arabic (used officially for Arab minority), English (most commonly used foreign language) |
| Italy | Italian (official), German (parts of Trentino-Alto Adige region are predominantly German speaking), French (small French-speaking minority in Valle d'Aosta region), Slovene (Slovene-speaking minority in the Trieste-Gorizia area) |
| Jamaica | English, English patois |
| Jan Mayen | void |
| Japan | Japanese |
| Jersey | English 94.5% (official), Portuguese 4.6%, other 0.9% (2001 census) |
| Jordan | Arabic (official), English (widely understood among upper and middle classes) |
| Kazakhstan | Kazakh (Qazaq, state language) 64.4%, Russian (official, used in everyday business, designated the "language of interethnic communication") 95% (2001 est.) |
| Kenya | English (official), Kiswahili (official), numerous indigenous languages |
| Kiribati | I-Kiribati, English (official) |
| Korea, North | Korean |
| Korea, South | Korean, English (widely taught in junior high and high school) |
| Kosovo | Albanian (official), Serbian (official), Bosnian, Turkish, Roma |
| Kuwait | Arabic (official), English widely spoken |
| Kyrgyzstan | Kyrgyz (official) 64.7%, Uzbek 13.6%, Russian (official) 12.5%, Dungun 1%, other 8.2% (1999 census) |