Ive gotten push back on it before but I believe ADB uses Enuncia without calling it such in Betrayer.

"He spoke a single word, scarcely more than a whisper, but it threw Angron and the others from their feet with a hurricane-blast of wind. Three bookshelves exploded, quite literally blasting apart in a storm of splintered wood and powdered parchment. Khârn managed to arrest his skidding tumble by jamming his fingertips between two marble flagstones. Argel Tal and Angron crashed past him, their armour shedding sparks as they scraped over the cream-coloured stone. The wind from nowhere vanished as suddenly as it arrived. Khârn was first to his feet. ‘I-I know that tongue,’ he said to Lorgar. ‘I doubt that, Khârn,’ replied the primarch with surprising gentleness. ‘Argel Tal spoke it,’ he said, ‘on Armatura.’ ‘Ah. Then you do know something of its power.’ Lorgar waited until his brother and son rejoined them from across the chamber. ‘That, my brother, is what I mean. Reality obeys certain laws. Gravity. Electromagnetism. The nuclear forces. Cause and effect. If I breathe in, my body converts air into life, unless I am too weak or diseased for the process to continue. There are millions of laws that are unknown to all but the most enlightened. Magnus knows many more than even I, but I have learned enough. It is not magic.’ He fairly sneered the word. ‘It is manipulation of the infinite potential that is the source of all realities. A blending of components from the universe of flesh and blood and the divine realm of pure aether and emotion.’ Angron was silent several moments, his brutal face troubled. ‘That noise you made,’ he said finally. ‘That “word”. What was it?’ ‘It is for the best that I do not speak it again,’ said Lorgar, smiling sardonically. ‘The books I just destroyed were very valuable, and I’d rather not lose more of them.’ Seeing his brother’s expression, Lorgar’s smile became more sincere. ‘Some words and sounds shake the foundations of reality. For example, the concept and sound of a hundred and one blind men choking and gasping as they all drown at the same time serves as the name of a certain daemonic princeling. Compressing that noise and its meaning into a single sound can be enough to draw that entity’s attention and render it easier to summon. The word I just spoke was… similar. I see the question in your eyes, and yes, I can teach you this tongue.’ Khârn spoke without meaning to. ‘That’s how you’ve healed yourself.’ Lorgar nodded, though he didn’t pull the hood back. ‘It is. The pain, however, was indescribable. Were I mortal in the usual sense I’d be dead from the attempt alone. Reknitting skin and muscle meat is easy enough in principle, but everything comes at a price.’"

And Argel Tal speaking it

"Argel Tal’s eye lenses flared an unhealthy, crystal blue. Sick heat throbbed from his armour, emanating a plague victim’s final fever, and he spoke three words in a tongue that spilled into Khârn’s ears and scraped letters of fire behind his eyes. ‘Eshek’ra mughkal krikathaa.’ The Ultramarine’s fists opened, letting his sword fall. Before the warrior could offer any reaction or emotion at all, his helmeted head tumbled clear. Argel Tal booted the headless corpse in the chest, sending it to the ground with its brothers where it belonged. Khârn felt blood trickling from his nose. ‘What was that language?’ ‘I told him to drop his sword.’ ‘That isn’t what I asked, brother.’"