It is a problem for Project Runeberg that ISO 639 does not define any two-letter language code for sami/lapp language(s). ISO 639-2 defines three-letter language codes, including "lap" for "Lapp languages".
| ISO 639 two letter code |
ISO 639-2 three letter code | Language |
| aa | Afar | |
| ab | Abkhazian | |
| af | Afrikaans | |
| am | Amharic | |
| ar | Arabic | |
| as | Assamese | |
| ay | Aymara | |
| az | Azerbaijani | |
| ba | Bashkir | |
| be | Byelorussian | |
| bg | Bulgarian | |
| bh | Bihari | |
| bi | Bislama | |
| bn | Bengali | |
| bo | Tibetan | |
| br | Breton | |
| ca | Catalan | |
| co | Corsican | |
| cs | Czech | |
| cy | Welsh | |
| da | Danish | |
| de | German | |
| dz | Bhutani | |
| el | Greek | |
| en | English | |
| eo | Esperanto | |
| es | Spanish | |
| et | Estonian | |
| eu | Basque | |
| fa | Persian | |
| fi | Finnish | |
| fj | Fiji | |
| fo | Faeroese | |
| fr | French | |
| fy | Frisian | |
| ga | Irish | |
| gd | Scots | |
| gl | Galician | |
| gn | Guarani | |
| gu | Gujarati | |
| ha | Hausa | |
| hi | Hindi | |
| hr | Croatian | |
| hu | Hungarian | |
| hy | Armenian | |
| ia | Interlingua | |
| ie | Interlingue | |
| ik | Inupiak | |
| in | Indonesian | |
| is | Icelandic | |
| it | Italian | |
| iw | Hebrew | |
| ja | Japanese | |
| ji | Yiddish | |
| jw | Javanese | |
| ka | Georgian | |
| kk | Kazakh | |
| kl | Greenlandic | |
| km | Cambodian | |
| kn | Kannada | |
| ko | Korean | |
| ks | Kashmiri | |
| ku | Kurdish | |
| ky | Kirghiz | |
| la | Latin | |
| lap | Lapp/sami | |
| ln | Lingala | |
| lo | Laotian | |
| lt | Lithuanian | |
| lv | Latvian | |
| lv | Latvian, Lettish | |
| mg | Malagasy | |
| mi | Maori | |
| mk | Macedonian | |
| ml | Malayalam | |
| mn | Mongolian | |
| mo | Moldavian | |
| mr | Marathi | |
| ms | Malay | |
| mt | Maltese | |
| my | Burmese | |
| na | Nauru | |
| ne | Nepali | |
| nl | Dutch | |
| no | Norwegian | |
| oc | Occitan | |
| or | Oriya | |
| pa | Punjabi | |
| pl | Polish | |
| ps | Pashto | |
| pt | Portuguese | |
| qu | Quechua | |
| rm | Rhaeto | |
| rn | Kirundi | |
| ro | Romanian | |
| ru | Russian | |
| rw | Kinyarwanda | |
| sa | Sanskrit | |
| sd | Sindhi | |
| sg | Sangro | |
| sh | Serbo-Croatian | |
| si | Singhalese | |
| sk | Slovak | |
| sl | Slovenian | |
| sm | Samoan | |
| sn | Shona | |
| so | Somali | |
| sq | Albanian | |
| sr | Serbian | |
| ss | Siswati | |
| st | Sesotho | |
| su | Sudanese | |
| sv | Swedish | |
| sw | Swahili | |
| ta | Tamil | |
| te | Tegulu | |
| tg | Tajik | |
| th | Thai | |
| ti | Tigrinya | |
| tk | Turkmen | |
| tl | Tagalog | |
| tn | Setswana | |
| to | Tonga | |
| tr | Turkish | |
| ts | Tsonga | |
| tt | Tatar | |
| tw | Twi | |
| uk | Ukrainian | |
| ur | Urdu | |
| uz | Uzbek | |
| vi | Vietnamese | |
| vo | Volapuk | |
| wo | Wolof | |
| xh | Xhosa | |
| yo | Yoruba | |
| zh | Chinese | |
| zu | Zulu |