About the Berthier surname
The surname Berthier has an onomastic interpretation that still needs to be placed in the history of each family line. The form of Berthier is compatible with French surname tradition. It may derive from an old given name, a place, a nickname, an occupation, or a regional variant; the historical form of the family line is needed to distinguish between these possibilities. Etymology can clarify how the surname formed, while the earliest records remain necessary to connect that explanation with a specific family line. The etymological interpretation should be compared with the earliest spellings and places associated with each family line.
Pronunciation:
Bèr-tié/bɛʁtje/