| English | eng-000 |
| optional | |
| Afrikaans | afr-000 | fakultatief |
| العربية | arb-000 | إختياري |
| العربية | arb-000 | اختياري |
| العربية | arb-000 | اِخْتِيَارِيّ |
| العربية | arb-000 | خياري |
| العربية | arb-000 | كيفي |
| Romániço | art-013 | facultativa |
| Romániço | art-013 | optiona |
| Romániço | art-013 | permisata |
| Romániço | art-013 | volitionasca |
| Universal Networking Language | art-253 | optional |
| Universal Networking Language | art-253 | optional(icl>adj,ant>obligatory) |
| Sambahsa-mundialect | art-288 | facultative |
| Sambahsa-mundialect | art-288 | optional |
| ISO 12620 | art-317 | optional |
| অসমীয়া ভাষা | asm-000 | ঐচ্ছিক |
| বাংলা | ben-000 | ̃ধীন |
| বাংলা | ben-000 | ঐচ্ছিক |
| български | bul-000 | незадължителен |
| български | bul-000 | факултативен |
| català | cat-000 | opcional |
| čeština | ces-000 | dobrovolný |
| čeština | ces-000 | doplňkový |
| čeština | ces-000 | fakultativní |
| čeština | ces-000 | nepovinný |
| čeština | ces-000 | volitelný |
| čeština | ces-000 | výběrový |
| سۆرانی | ckb-000 | ئارهزوومهندانه |
| 普通话 | cmn-000 | 不是必需的 |
| 普通话 | cmn-000 | 任意的 |
| 普通话 | cmn-000 | 任意选择的 |
| 普通话 | cmn-000 | 任选的 |
| 普通话 | cmn-000 | 可任意选择的 |
| 普通话 | cmn-000 | 可选择 |
| 普通话 | cmn-000 | 可选择的 |
| 普通话 | cmn-000 | 可选的 |
| 普通话 | cmn-000 | 自选 |
| 普通话 | cmn-000 | 选择性的 |
| 普通话 | cmn-000 | 选购的 |
| 普通话 | cmn-000 | 随意 |
| 普通话 | cmn-000 | 随意的 |
| 國語 | cmn-001 | 任選的 |
| 國語 | cmn-001 | 可以任意選擇的 |
| 國語 | cmn-001 | 可以任選的 |
| 國語 | cmn-001 | 可任意選擇的 |
| 國語 | cmn-001 | 可任選的 |
| 國語 | cmn-001 | 可選擇 |
| 國語 | cmn-001 | 可選擇的 |
| 國語 | cmn-001 | 自選 |
| 國語 | cmn-001 | 選擇的 |
| 國語 | cmn-001 | 隨意的 |
| 國語 | cmn-001 | 非強制的 |
| Middle Cornish | cnx-000 | dewisel |
| Middle Cornish | cnx-000 | dre dhewis |
| Kernowek | cor-000 | dewisel |
| Kernowek | cor-000 | dewysek |
| Kernowek | cor-000 | dre dhewis |
| dansk | dan-000 | fakultativ |
| dansk | dan-000 | valgfrit |
| Deutsch | deu-000 | Belieben |
| Deutsch | deu-000 | Freiwilligkeit |
| Deutsch | deu-000 | Option |
| Deutsch | deu-000 | Willkür |
| Deutsch | deu-000 | fakultativ |
| Deutsch | deu-000 | freie Wahl |
| Deutsch | deu-000 | freier Wille |
| Deutsch | deu-000 | freigestellt |
| Deutsch | deu-000 | freiwillig |
| Deutsch | deu-000 | optional |
| Deutsch | deu-000 | unverbindlich |
| Deutsch | deu-000 | wahlfrei |
| Deutsch | deu-000 | wahlweise |
| eesti | ekk-000 | fakultatiivne |
| eesti | ekk-000 | vabal valikul |
| eesti | ekk-000 | valikuline |
| ελληνικά | ell-000 | κατ' εκλογήν |
| ελληνικά | ell-000 | προαιρετικός |
| English | eng-000 | alternate |
| English | eng-000 | alternative |
| English | eng-000 | any |
| English | eng-000 | arbitrary |
| English | eng-000 | at will |
| English | eng-000 | discretion |
| English | eng-000 | discretionary |
| English | eng-000 | dispensable |
| English | eng-000 | electable |
| English | eng-000 | elective |
| English | eng-000 | eligible |
| English | eng-000 | extracurricular |
| English | eng-000 | extraneous |
| English | eng-000 | extrinsic |
| English | eng-000 | facultative |
| English | eng-000 | free will |
| English | eng-000 | if desired |
| English | eng-000 | inessential |
| English | eng-000 | needless |
| English | eng-000 | non-obligatory |
| English | eng-000 | non-specific |
| English | eng-000 | not obligatory |
| English | eng-000 | not required |
| English | eng-000 | opt |
| English | eng-000 | opt. |
| English | eng-000 | peripheral |
| English | eng-000 | permissive |
| English | eng-000 | random |
| English | eng-000 | selective |
| English | eng-000 | substitute |
| English | eng-000 | unessential |
| English | eng-000 | unneeded |
| English | eng-000 | unrequired |
| English | eng-000 | unspecified |
| English | eng-000 | voluntary |
| Esperanto | epo-000 | fakultativa |
| Esperanto | epo-000 | laŭvola |
| Esperanto | epo-000 | malnepra |
| Esperanto | epo-000 | nedeviga |
| Esperanto | epo-000 | opcia |
| Esperanto | epo-000 | permisata |
| Esperanto | epo-000 | sendeviga |
| euskara | eus-000 | aukerako |
| euskara | eus-000 | hautazko |
| føroyskt | fao-000 | valtøkur |
| suomi | fin-000 | omavalintainen |
| suomi | fin-000 | valinnainen |
| suomi | fin-000 | vapaaehtoinen |
| français | fra-000 | arbitraire |
| français | fra-000 | au choix |
| français | fra-000 | en option |
| français | fra-000 | facultatif |
| français | fra-000 | libre |
| français | fra-000 | optionnel |
| français | fra-000 | quelconque |
| galego | glg-000 | opcional |
| galego | glg-000 | optativo |
| yn Ghaelg | glv-000 | reihyssagh |
| ગુજરાતી | guj-000 | ઐચ્છિક |
| ગુજરાતી | guj-000 | ફરજિયાત નહિ |
| ગુજરાતી | guj-000 | વૈકલ્પિક |
| हिन्दी | hin-000 | इच्छानुसार |
| हिन्दी | hin-000 | ऐच्छिक |
| हिन्दी | hin-000 | रुच्यधीन |
| हिन्दी | hin-000 | वैकल्पिक |
| hrvatski | hrv-000 | alternativan |
| hrvatski | hrv-000 | fakultativan |
| hrvatski | hrv-000 | izborni |
| hrvatski | hrv-000 | neobavezan |
| hrvatski | hrv-000 | neobvezan |
| hrvatski | hrv-000 | neobvezatan |
| hrvatski | hrv-000 | neobvezatno |
| hrvatski | hrv-000 | opcionalan |
| hrvatski | hrv-000 | opcionalni |
| hrvatski | hrv-000 | po izboru |
| hrvatski | hrv-000 | po volji |
| hrvatski | hrv-000 | prepušten slobodnom izboru |
| magyar | hun-000 | fakultatív |
| magyar | hun-000 | nem kötelező |
| magyar | hun-000 | szabadon választható |
| magyar | hun-000 | tetszőleges |
| արևելահայերեն | hye-000 | նախասիրական |
| Ido | ido-000 | fakultativa |
| Ido | ido-000 | permisata |
| Interlingue | ile-000 | facultativ |
| interlingua | ina-000 | facultative |
| interlingua | ina-000 | optional |
| bahasa Indonesia | ind-000 | fakultatif |
| bahasa Indonesia | ind-000 | opsional |
| bahasa Indonesia | ind-000 | pilihan |
| íslenska | isl-000 | frjáls |
| íslenska | isl-000 | valfrjáls |
| íslenska | isl-000 | valkvæður |
| italiano | ita-000 | discrezione |
| italiano | ita-000 | facoltativo |
| italiano | ita-000 | libero |
| italiano | ita-000 | obbligatorio |
| italiano | ita-000 | opzionale |
| italiano | ita-000 | volontario |
| 日本語 | jpn-000 | オプショナル |
| 日本語 | jpn-000 | 代わりの |
| 日本語 | jpn-000 | 任意 |
| 日本語 | jpn-000 | 任意の |
| 日本語 | jpn-000 | 択一的な |
| 日本語 | jpn-000 | 要否 |
| 日本語 | jpn-000 | 選択の |
| 日本語 | jpn-000 | 随意 |
| 日本語 | jpn-000 | 随意の |
| 日本語 | jpn-000 | 随意的 |
| にほんご | jpn-002 | かわりの |
| にほんご | jpn-002 | ずいい |
| にほんご | jpn-002 | ずいいの |
| にほんご | jpn-002 | せんたくの |
| にほんご | jpn-002 | たくいつてきな |
| にほんご | jpn-002 | にんいの |
| Taqbaylit | kab-000 | umadhghir |
| ქართული | kat-000 | არასავალდებულო |
| ქართული | kat-000 | ნებაყოფლობითი |
| қазақ | kaz-000 | нәпіл |
| монгол | khk-000 | албан журмын бус |
| монгол | khk-000 | заавал биш |
| монгол | khk-000 | сайн дурын |
| монгол | khk-000 | туслах чанарын |
| ភាសាខ្មែរ | khm-000 | ស្រេច ចិត្ត |
| кыргыз | kir-000 | қосымша |
| 한국어 | kor-000 | 기능의 |
| 한국어 | kor-000 | 대신의 |
| 한국어 | kor-000 | 선택 과목 |
| 한국어 | kor-000 | 수의의 |
| 한국어 | kor-000 | 우발적인 |
| 한국어 | kor-000 | 허용적인 |
| Lingua Franca Nova | lfn-000 | elejable |
| Lingua Franca Nova | lfn-000 | nonobligada |
| Lingua Franca Nova | lfn-000 | nonobligante |
| Lingua Franca Nova | lfn-000 | si desirada |
| lietuvių | lit-000 | fakultatyvus |
| मराठी | mar-000 | इच्छेप्रमाणे |
| मराठी | mar-000 | ऐच्छिक |
| मराठी | mar-000 | पर्यायी |
| मराठी | mar-000 | वैकल्पिक |
| мокшень кяль | mdf-000 | полафневи |
| mokshenj kalj | mdf-001 | polafnevi |
| олык марий | mhr-000 | факультативный |
| Huzhu Mongghul | mjg-001 | ligha |
| Minhe Mangghuer | mjg-002 | aligha |
| македонски | mkd-000 | изборен |
| Malti | mlt-000 | mhux obbligatorju |
| эрзянь кель | myv-000 | аволь обязательной |
| Tâi-gí | nan-003 | sóan-te̍k ĕ |
| Tâi-gí | nan-003 | sŭi-ì ĕ |
| Tâi-gí | nan-003 | ē-sóan-tit |
| Nederlands | nld-000 | facultatief |
| Nederlands | nld-000 | niet verplicht |
| Nederlands | nld-000 | optioneel |
| Nederlands | nld-000 | vrijblijvend |
| bokmål | nob-000 | fakultativ |
| bokmål | nob-000 | valgfri |
| occitan | oci-000 | facultatiu |
| occitan | oci-000 | opcional |
| Old Cornish | oco-000 | dewisel |
| Old Cornish | oco-000 | dre dhewis |
| Plautdietsche Sproak | pdt-000 | utwälent |
| Mennoniten-Plautdietsch | pdt-001 | ütwälent |
| فارسی | pes-000 | اختیاری |
| فارسی | pes-000 | دل بخواه |
| فارسی | pes-000 | غیر واجب |
| polski | pol-000 | dowolny |
| polski | pol-000 | fakultatywny |
| português | por-000 | facultativo |
| português | por-000 | opcional |
| română | ron-000 | facultativ |
| русский | rus-000 | дискреционный |
| русский | rus-000 | диспозитивный |
| русский | rus-000 | дополнительно |
| русский | rus-000 | дополнительный |
| русский | rus-000 | зависящий от усмотрения |
| русский | rus-000 | заказной |
| русский | rus-000 | необяза́тельный |
| русский | rus-000 | необязательный |
| русский | rus-000 | по желанию |
| русский | rus-000 | по отдельному заказу |
| русский | rus-000 | произвольный |
| русский | rus-000 | факультати́вный |
| русский | rus-000 | факультативный |
| संस्कृतम् | san-000 | आभिप्रायिक |
| संस्कृतम् | san-000 | ऐच्छिक |
| संस्कृतम् | san-000 | पाक्षिक |
| संस्कृतम् | san-000 | वैकल्पिक |
| संस्कृतम् | san-000 | वैभाषिक |
| संस्कृतम् | san-000 | सविकल्प सविकल्पक |
| lingua siciliana | scn-000 | facultativu |
| lingua siciliana | scn-000 | opzionali |
| slovenčina | slk-000 | dobrovoľný |
| slovenčina | slk-000 | fakultatívny |
| slovenčina | slk-000 | nepovinný |
| slovenčina | slk-000 | voliteľný |
| slovenčina | slk-000 | zvláštny |
| slovenčina | slk-000 | ľubovoľný |
| slovenščina | slv-000 | dovoljen |
| slovenščina | slv-000 | fakultativen |
| slovenščina | slv-000 | neobvezen |
| slovenščina | slv-000 | obvezen |
| slovenščina | slv-000 | poljuben |
| español | spa-000 | discrecional |
| español | spa-000 | facultativo |
| español | spa-000 | opcional |
| español | spa-000 | optativo |
| español | spa-000 | potestativo |
| srpski | srp-001 | fakultativan |
| srpski | srp-001 | neobavezan |
| srpski | srp-001 | po izboru |
| srpski | srp-001 | po volji |
| svenska | swe-000 | fakultativ |
| svenska | swe-000 | fakultativt |
| svenska | swe-000 | frivillig |
| svenska | swe-000 | frivilligt |
| svenska | swe-000 | valfri |
| svenska | swe-000 | valfritt |
| Kiswahili | swh-000 | -a hiari |
| తెలుగు | tel-000 | ఐచ్ఛిక |
| తెలుగు | tel-000 | ఐచ్ఛికం |
| తెలుగు | tel-000 | వికల్పం |
| తెలుగు | tel-000 | వైకల్పం |
| తెలుగు | tel-000 | వైకల్పిక |
| తెలుగు | tel-000 | వైకల్పికం |
| తెలుగు | tel-000 | వైభాషికం |
| ภาษาไทย | tha-000 | ซึ่งเปิดให้เลือก |
| ภาษาไทย | tha-000 | ซึ่งเป็นทางเลือก |
| ภาษาไทย | tha-000 | มีทางเลือก |
| ภาษาไทย | tha-000 | เกี่ยวกับสิทธิ |
| ภาษาไทย | tha-000 | เกี่ยวกับอำนาจ |
| ภาษาไทย | tha-000 | โดยสมัครใจ |
| ภาษาไทย | tha-000 | ให้เลือกได้ |
| ภาษาไทย | tha-000 | ไม่จําเป็น |
| ภาษาไทย | tha-000 | ไม่สําคัญ |
| türkmençe | tuk-000 | islege görä |
| türkmençe | tuk-000 | meýletin |
| Türkçe | tur-000 | ihtiyari |
| Türkçe | tur-000 | istemli |
| Türkçe | tur-000 | isteğe bağlı |
| Türkçe | tur-000 | opsiyonel |
| Türkçe | tur-000 | opsiyonlu |
| Türkçe | tur-000 | seçimli |
| Türkçe | tur-000 | seçmeli |
| Türkçe | tur-000 | zorunlu olmayan |
| Talossan | tzl-000 | facültatíu |
| اردو | urd-000 | اختیاری |
| tiếng Việt | vie-000 | không bắt buộc |
| tiếng Việt | vie-000 | tuỳ ý |
| tiếng Việt | vie-000 | để cho chọn |
| èdè Yorùbá | yor-000 | wọ̀fún |
| èdè Yorùbá | yor-000 | yíyàn |
| èdè Yorùbá | yor-000 | èyí tí ó wu ni |
| Bahasa Malaysia | zsm-000 | pilihan |