A probable cladistic tree of IE
graph TD; IE[Indo-European] An[Anatolian] NIE[Nuclear IE] Toch[Tocharian] WIE[Core IE] ItCe[Italo-Celtic] CIE[Central IE] Ce[Celtic] It[Italic] ?[dialect chain?] Gk[Greek] Ar[Armenian] Al[*Albanian] Gmc[Germanic] BSl[Balto-Slavic] II[Indo-Iranian] IE-->An IE-->NIE NIE-->Toch NIE-->WIE WIE-->ItCe ItCe-->Ce ItCe-->It WIE-->CIE CIE-->? CIE-->Gk CIE-->Ar CIE-->Al ?-->Gmc ?-->BSl ?-->II
Internal nomenclature and structure from 2017. From Proto-Indo-European to Proto-Germanic.