Bruce R. McConkie describes the "Adamic language" as pure and beautiful.
"Adamic Language," in Bruce R. McConkie, Mormon Doctrine (Salt Lake City: Bookcraft, 1958), 18-19
Adamic Language. See BOOK OF REMEMBRANCE, GAZELAM, LANGUAGES, TONGUES.
In the beginning God gave Adam a language that was pure, perfect, and undefiled. This Adamic language, now unknown, was far superior to any tongue which is presently extant. For instance, the name of God the Father, in this original language, is Man of Holiness, signifying that he is a Holy Man and not a vague spiritual essence. (Moses 6:57.)
The first language spoken by mortals was either the celestial tongue of the Gods or such adaptation of it as was necessary to meet the limitations of mortality; and Adam and his posterity had power to speak, read, and write it. (Way to Perfection, pp. 60-69.) In writing of the saints in the day of the first man, Moses says: "And a book of remembrance was kept, ... in the language of Adam, for it was given unto as many as called upon God to write by the spirit of inspiration; And by them their children were taught to read and write, having a language which was pure and undefiled." (Moses 6:5-6.)
The beauty and power of this Adamic language is indicated by a statement made by Moroni to the Lord about the Brother of Jared (who spoke the original and pure language) : "Thou madest him that the things which he wrote were mighty even as thou art, unto the overpowering of man to read them." (Ether 12:24.)
During the millennium, it appears that men will again have power to speak and write the Adamic language. Of that day the Lord says: "Will I tum to the people a pure language, that they may all call upon the name of the Lord, to serve him with one consent." (Zeph. 3:9.) In some instances when the saints speak in tongues, the language impressed upon them by the power . of the Spirit is the pure Adamic tongue.