All languages in Europe ... and on earth ... one day;)
Afrikaans, Albanian, Arabic, Azerbaijani, Basque, Belarusian, Bosnian, Breton, Bulgarian, Catalan, Chechen, Chinese, Cornish, Corsican, Croatian, Czech, Dalmatian, Danish, Doric, Dutch, Estonian, Faroese, French, Galician, German, Georgian, Greek, Haitian Creole, Hawaiian, Hebrew, Hindi, Hungarian, Icelandic, Italian, Ladino, Latin, Latvian, Lithuanian, Luxembourgish, Macedonian, Malagasy, Malay, Maltese, Manx, Mauritian Creole, Montenegrin, Norwegian, Polish, Portuguese - Portugal, Portuguese - Brazil, Provençal, Romanian, Russian, Sanskrit, Sardinian, Seychellois Creole, Serbian, Sinhala, Shona, Slovak, Slovene, Spanish, Swahili, Swedish, Tagalog, Tok Pisin, Turkish, Turkmen, Ukrainian, Urdu, Venetian, Welsh, West Frisian, Yiddish, Yoruba.
Language families and branches.
Austronesian, Bantu, Celtic, Creoles, Germanic, Indo-Aryan, Indo-European, Kartvelian, Polynesian, Romance, Semitic, Slavic, Turkic.
Afrikaans, Albanian, Arabic, Belsarusian, Bosnian, Bulgarian, Catalan, Chinese, Croatian, Czech, Danish, Dutch, Estonian, French, Finnish, German, Greek, Hebrew, Hindi, Hungarian, Icelandic, Italian, Latvian, Lithuanian, Macedonian, Maltese, Norwegian, Polish, Portguese (Brazil), Portguese (Portugal), Romanian, Russian, Slovak, Spanish, Swahili, Swedish, Tagalog, Turkish, Urdu, Ukrainian, Welsh, Yiddish.
Afrikaans, Bulgarian, Italian, Lithuanian, Polish, Romanian, Russian, Spanish.
Use one language to learn another using language pairs (laddering)
Word frequency lists, French words, Italian words, German words, Polish words, Spanish words.