The language of Kabbalists is a language in the full sense of the word: very precise, both concerning root and branch and concerning cause and consequence. It has a unique merit of being able to express subtle details in this language without any limits. Also, through it, it is possible to approach the desired matter directly, without the need to connect it with what precedes it or follows it.
Baal HaSulam, “The Teaching of the Kabbalah and Its Essence”
Kabbalists have found a set and annotated vocabulary, sufficient to create an excellent spoken language. It enables them to converse with one another of the dealings in the Spiritual Roots in the Upper Worlds by merely mentioning the lower, tangible branch in this world that is well defined to our corporeal senses. The listeners understand the Upper Root to which this corporeal branch points because it is related to it, being its imprint.
Baal HaSulam, “The Essence of the Wisdom of Kabbalah”
All the beings of the tangible creation and all their instances have become to them like well-defined words and names, indicating the High Spiritual Roots. Although there cannot be a verbal expression in their spiritual place, as it is above any imagination, they have earned the right to be expressed by utterance through their branches, arranged before our senses here in the tangible world.
Baal HaSulam, “The Essence of the Wisdom of Kabbalah”
All the words and utterances our lips pronounce cannot help us convey even a single word from the spiritual, Godly matters, above the imaginary time and space. Instead, there is a special language for these matters, being the Language of the Branches, indicating their relation to their Upper Roots.
However, this language, though extremely suitable for its task of delving into the studies of this wisdom, more than other languages, is only so if the listener is wise in his own right, meaning that he knows and understands the way the branches relate to their roots.
Baal HaSulam, “The Essence of the Wisdom of Kabbalah”
All those who attained the Light of the Creator through their work wanted all those succeeding them to enjoy what they had already discovered, as well. Therefore, they named each and every attainment so they would be able to understand their intentions and the attainments that they attained, and thus form a common language with each other.
Rabash, “Letter no. 19”