Text Section 148
(2) Tibetan people believe that all buddhas of the three times have previously taught, presently teach and in the future will continue to teach in Sanskrit. As the language of all the buddhas, Sanskrit [legs sbyar] is considered to be the divine language [lha’i skad] and to carry tremendous blessings. When the reader recites the title in Sanskrit, therefore, the stream of blessing of all the buddhas will enter into his mind.
Buddhas teach the dharma through the miraculous display of their corresponding speech [gsung rjes su mthun pa’i cho ’phrul]. This means that each member of the audience hears the teachings in his own language. Nāgas, for instance, will perceive the teachings in nāga language; gods in god language; and humans in their personal language or dialect.
The buddhas, therefore, do not need interpreters because they can communicate directly with each being according to his culture, language, capacities and needs. One should not limit the Buddha’s language to Sanskrit alone, but since the dharma was translated into Tibetan from Sanskrit texts, Tibetan people consider Sanskrit to be the language of all the buddhas.