Site Language Name in English

If you 'inspect' the selection you can see their ISO language codes

I have extracted that for you and made slightly readable - you will still need to lookup the codes



"af" lang="af" Afrikaans
"am" lang="am" ????
"arg" lang="an" Aragonés
"ar" lang="ar" ???????
"ary" lang="ar" ??????? ????????
"as" lang="as" ???????
"azb" lang="az" ????? ?????????
"az" lang="az" Az?rbaycan dili
"bel" lang="be" Беларуская мова
"bg_BG" lang="bg" Български
"bn_BD" lang="bn" ?????
"bo" lang="bo" ???????
"bs_BA" lang="bs" Bosanski
"ca" lang="ca" Català
"ceb" lang="ceb" Cebuano
"cs_CZ" lang="cs" ?e?tina
"cy" lang="cy" Cymraeg
"da_DK" lang="da" Dansk
"de_DE_formal" lang="de" Deutsch (Sie)
"de_CH" lang="de" Deutsch (Schweiz)
"de_CH_informal" lang="de" Deutsch (Schweiz, Du)
"de_AT" lang="de" Deutsch (?sterreich)
"de_DE" lang="de" Deutsch
"dsb" lang="dsb" Dolnoserb??ina
"dzo" lang="dz" ??????
"el" lang="el" Ελληνικ?
"en_GB" lang="en" English (UK)
"en_ZA" lang="en" English (South Africa)
"en_CA" lang="en" English (Canada)
"en_AU" lang="en" English (Australia)
"en_NZ" lang="en" English (New Zealand)
"eo" lang="eo" Esperanto
"es_MX" lang="es" Espa?ol de México
"es_EC" lang="es" Espa?ol de Ecuador
"es_VE" lang="es" Espa?ol de Venezuela
"es_DO" lang="es" Espa?ol de República Dominicana
"es_PE" lang="es" Espa?ol de Perú
"es_UY" lang="es" Espa?ol de Uruguay
"es_CL" lang="es" Espa?ol de Chile
"es_PR" lang="es" Espa?ol de Puerto Rico
"es_ES" lang="es" Espa?ol
"es_GT" lang="es" Espa?ol de Guatemala
"es_CR" lang="es" Espa?ol de Costa Rica
"es_AR" lang="es" Espa?ol de Argentina
"es_CO" lang="es" Espa?ol de Colombia
"et" lang="et" Eesti
"eu" lang="eu" Euskara
"fa_IR" lang="fa" ?????
"fa_AF" lang="fa" (????? (?????????
"fi" lang="fi" Suomi
"fr_FR" lang="fr" Fran?ais
"fr_BE" lang="fr" Fran?ais de Belgique
"fr_CA" lang="fr" Fran?ais du Canada
"fur" lang="fur" Friulian
"fy" lang="fy" Frysk
"gd" lang="gd" Gàidhlig
"gl_ES" lang="gl" Galego
"gu" lang="gu" ???????
"haz" lang="haz" ????? ??
"he_IL" lang="he" ????????
"hi_IN" lang="hi" ??????
"hr" lang="hr" Hrvatski
"hsb" lang="hsb" Hornjoserb??ina
"hu_HU" lang="hu" Magyar
"hy" lang="hy" ???????
"id_ID" lang="id" Bahasa Indonesia
"is_IS" lang="is" íslenska
"it_IT" lang="it" Italiano
"ja" lang="ja" 日本語
"jv_ID" lang="jv" Basa Jawa
"ka_GE" lang="ka" ???????
"kab" lang="kab" Taqbaylit
"kk" lang="kk" ?аза? т?л?
"km" lang="km" ?????????
"kn" lang="kn" ?????
"ko_KR" lang="ko" ???
"ckb" lang="ku" ??????
"kir" lang="ky" Кыргызча
"lo" lang="lo" ???????
"lt_LT" lang="lt" Lietuvi? kalba
"lv" lang="lv" Latvie?u valoda
"mk_MK" lang="mk" Македонски ?азик
"ml_IN" lang="ml" ??????
"mn" lang="mn" Монгол
"mr" lang="mr" ?????
"ms_MY" lang="ms" Bahasa Melayu
"my_MM" lang="my" ?????
"nb_NO" lang="nb" Norsk bokm?l
"ne_NP" lang="ne" ??????
"nl_BE" lang="nl" Nederlands (Belgi?)
"nl_NL" lang="nl" Nederlands
"nl_NL_formal" lang="nl" Nederlands (Formeel)
"nn_NO" lang="nn" Norsk nynorsk
"oci" lang="oc" Occitan
"pa_IN" lang="pa" ??????
"pl_PL" lang="pl" Polski
"ps" lang="ps" ????
"pt_AO" lang="pt" Português de Angola
"pt_PT_ao90" lang="pt" Português (AO90)
"pt_BR" lang="pt" Português do Brasil
"pt_PT" lang="pt" Português
"rhg" lang="rhg" Ruáinga
"ro_RO" lang="ro" Roman?
"ru_RU" lang="ru" Русский
"sah" lang="sah" Сахалыы
"snd" lang="sd" ????
"si_LK" lang="si" ?????
"sk_SK" lang="sk" Sloven?ina
"skr" lang="skr" ???????
"sl_SI" lang="sl" Sloven??ina
"sq" lang="sq" Shqip
"sr_RS" lang="sr" Српски ?език
"sv_SE" lang="sv" Svenska
"sw" lang="sw" Kiswahili
"szl" lang="szl" ?lōnsk? g?dka
"ta_IN" lang="ta" ?????
"ta_LK" lang="ta" ?????
"te" lang="te" ??????
"th" lang="th" ???
"tl" lang="tl" Tagalog
"tr_TR" lang="tr" Türk?e
"tt_RU" lang="tt" Татар теле
"tah" lang="ty" Reo Tahiti
"ug_CN" lang="ug" ????????
"uk" lang="uk" Укра?нська
"ur" lang="ur" ????
"uz_UZ" lang="uz" O‘zbekcha
"vi" lang="vi" Ti?ng Vi?t
"zh_HK" lang="zh" 香港中文
"zh_TW" lang="zh" 繁體中文
"zh_CN" lang="zh" 简体中文

You could simply add the following line in wp-config.php:
define ('WPLANG', 'ar');

Hi, @tobifjellner, @alanfuller

Thank you very much!