Ramban on the Leshon haQodesh - Hebrew as the 'Holy Language'

"This is also the reason, I believe, for why our Sages call the language of the Torah 'the Holy Language' (Leshon haQodesh); it is because the words of the Torah and the prophecies and all kinds of other holy words were all said by the prophets to the people in this language. And furthermore, you see that it is the language in which the Holy One, Blessed is He - may His Name be blessed - speaks with His prophets and with His congregation, such as the first two Commandments, 'I am YHVH your God' and 'there shall not be for you other gods' as well as all the other communications from God recorded in the Torah and in the books of prophecy.

"And furthermore it is in that language that God is called by His sacred Names: El, Elohim, Tzeva'ot, Shaddai, Yah, and the ineffable, four-letter, great and unique Name. And furthermore it is in that language that He created His world and gave names to the heaven and the earth and everything that is in them. And furthermore, His angels and all His heavenly hosts - all of them He calls by names in that language, such as 'Michael' and 'Gabriel'. And furthermore it is in that language that He gave names to the holy ones who are on earth, such as to Abraham, Isaac, Solomon, and others besides him."

-- Rabbi Moshe ben Nachman (Ramban), Commentary on the Torah - Exodus 30:13.