The "language" of God is the various means of His "communication" with man, which is realized by manifestation of the Divine perfections, the greatness of His Creations and by contemplation, by man's awareness of the harmony of the surrounding world.
"Language" of God is also the Revelations of the Wisdom of His Will, His Commandments, expressed in the Holy Scriptures by His "Mouth," that is, by His Messengers - Melchizedek, the Patriarchs, the Prophets, Jesus Christ, the Apostles, all the Righteous.
The "tongue" of God is also the inner "Voice" of man - his conscience, originally given to him by God.
"Man's "tongue" is the symbol of the expression of man's worldview, manifested in his way of life, which reflects his inner essence, is the "spiritual imprint" of his personality, the moral, moral "handwriting.
"The language" of the righteous man is the embodiment of godly thoughts and a righteous way of life by the implementation of God's Commandments, by the proclamation of His Will among the sinful living peoples.
The "tongue" of the sinner is the embodiment of his sinful thoughts, his false worldview, a varied expression, a display of his vicious way of life.