| Subfamily | Group | Subgroup | Languages and Principal Dialects |
| Anatolian | Hieroglypic Hittite*, Hittite (Kanesian)*, Luwian*, Lycian*, Lydian*, Palaic* | ||
| Baltic | Latvian (Lettish), Lithuanian, Old Prussian* | ||
| Celtic | Brythonic | Breton, Cornish*, Welsh | |
| Celtic | Continental | Gaulish* | |
| Celtic | Goidelic or Gaelic | Irish (Irish Gaelic), Manx*, Scottish Gaelic | |
| Germanic | East Germanic | Burgundian*, Gothic*, Vandalic* | |
| Germanic | North Germanic | Old Norse* (see Norse): Danish, Faeroese, Icelandic, Norwegian, Swedish | |
| Germanic | West Germanic (see Grimm's law) | High German | German, Yiddish |
| Germanic | West Germanic (see Grimm's law) | Low German | Afrikaans, Dutch, English, Flemish, Frisian, Plattdeutsch (see German language) |
| Greek | Aeolic*, Arcadian*, Attic*, Byzantine Greek*, Cyprian*, Doric*, Ionic*, KoinE*, Modern Greek | ||
| Indo-Iranian | Dardic or Pisacha | Kafiri, Kashmiri, Khowar, Kohistani, Romany (Gypsy), Shina | |
| Indo-Iranian | Indic or Indo-Aryan | Pali*, Prakrit*, Sanskrit*, Vedic* | |
| Indo-Iranian | Indic or Indo-Aryan | Central Indic | Hindi, Hindustani, Urdu |
| Indo-Iranian | Indic or Indo-Aryan | East Indic | Assamese, Bengali, Bihari, Oriya |
| Indo-Iranian | Indic or Indo-Aryan | Northwest Indic | Punjabi, Sindhi |
| Indo-Iranian | Indic or Indo-Aryan | Pahari | Central Pahari, Eastern Pahari (Nepali), Western Pahari |
| Indo-Iranian | Indic or Indo-Aryan | South Indic | Marathi (including major dialect Konkani), Singhalese (Sinhalese) |
| Indo-Iranian | Indic or Indo-Aryan | West Indic | Bhili, Gujarati, Rajasthani (many dialects) |
| Indo-Iranian | Iranian | Avestan*, Old Persian* | |
| Indo-Iranian | Iranian | East Iranian | Baluchi, Khwarazmian*, Ossetic, Pamir dialects, Pushtu (Afghan), Saka (Khotanese)*, Sogdian*, Yaghnobi |
| Indo-Iranian | Iranian | West Iranian | Kurdish, Pahlavi (Middle Persian)*, Parthian*, Persian (Farsi), Tajiki |
| Italic | (Non-Romance) | Faliscan*, Latin, Oscan*, Umbrian* | |
| Italic | Romance or Romanic | Eastern Romance | Italian, Rhaeto-Romanic, Romanian, Sardinian |
| Italic | Romance or Romanic | Western Romance | Catalan, French, Ladino, Portuguese, Provençal, Spanish |
| Slavic or Slavonic | East Slavic | Belorussian (White Russian), Russian, Ukrainian | |
| Slavic or Slavonic | South Slavic | Bulgarian, Church Slavonic*, Macedonian, Serbo-Croatian, Slovenian | |
| Slavic or Slavonic | West Slavic | Czech, Kashubian, Lusatian (Sorbian or Wendish), Polabian*, Polish, Slovak | |
| Thraco-Illyrian | Albanian, Illyrian*, Thracian* | ||
| Thraco-Phrygian | Armenian, Grabar (Classical Armenian)*, Phrygian* | ||
| Tokharian (W China) | Tokharian A (Agnean)*, Tokharian B (Kuchean)* |