Who says that all high mountains are called Alpes by Celts?
The English word Alps derives from the Latin Alpes (through French). Maurus Servius Honoratus, an ancient commentator of Virgil, says in his commentary (A. X 13) that all high mountains are called Alpes by Celts. The term may be common to Italo-Celtic, because the Celtic languages have terms for high mountains derived from alp.