{{reply to|ivanbranco}} Hi Ivan,

The official names of localities, hamlets and villages in Valle d'Aosta / Vallée d'Aoste are determined by the municipalities in consultation with and sent to the president of the autonomous region for approval, which is usually done by regional decree. Not all municipalities of Aosta Valley have done this, but most have. You can consult a full list of official toponyms here: https://www.regione.vda.it/enti_locali/cartella_i.asp?pk_cartelle=183

As it turns out, many toponyms are simply incorrect on digital cartography websites such as OpenStreetMap, Google Maps and Apple Maps (in ascending order of errors). As for alternative, local or old names, they may be added using alt_name I suppose, but I have solely relied on official toponyms approved by law for my edits. Happy to discuss specific toponyms if you have specific questions about each of them.