And God said, “LET THERE BE LIGHT,” and there was light.
Every letter and sound of Enochian is a hieroglyph or phoneme of staggering cosmic energy and geometric complexity that taps directly into the Power Cosmic to frame that energy into more specific constructs. It is not merely language or a means of conveying ideas; it is the source code of reality, which defines the universe itself.
Few creatures are capable of channeling the Power Cosmic through the Angelic language. The intense focus and discipline required to hold even the least of these geometries in place as a mental construct is beyond most mortal minds. Those who can, use the Enochian language to redefine reality with every word from their mouth. The full knowledge of Enochian is largely guarded by the Archangels and curated by Heaven's record-keeper, Metatron.
The Vulgate Enochian language, or 'Common Enochian, is the language that the Host uses to communicate with each other. It is both an oral and written language and has no inherent magical qualities. The Abyssal realms, especially Hell, speak a corrupted version of this language they mockingly refer to as Infernal Enochian.
Enochian and Magic
Virtually every mortal culture with an affinity for magic has, over time, developed complex workings that vaguely emulate Enochian. But even among the Wise, very few understand the connection to Enochian or are even aware of it in a conceptual sense.
For an aspiring magus spellwork is going to be in a strange language and possibly require many peculiar components metaphysically related to the task at hand. It is often very idiosyncratic, derived from the trappings of culture it originated from. A Taoist fangshi might write complex calligraphy on sheets of white paper to summon a storm, while a shaman from the First Nations could call rain with a dance and ritual song. Both of these are crude attempts to emulate Enochian.
If the world were a video game, Enochian is assembly language of microprocessors, and mortal magic is spamming backflips until the character can clip through walls.
Compensating for mortal inadequacies causes the difficulty of spellcasting to increase exponentially with the scope thereof. Many become trapped in their systems, unable to grasp the deeper concepts of the universe over the oft-conflicting of their own systems of magic. And because all mortal systems are inherently flawed compared to the perfect language of the universe, it becomes common even among the Wise to reach a point where their competence can take them no further.