[quote=@ERode]
Right was wondering, Nanaya. So far, most of us have been doing essence hijinks without incantations to begin with, but the advantage of an overcharged key line is, in fact, incantatonless spellcasting. Is that something to observe going forwards? And since it’s primal, I’m guessing that “speak incantations in reverse” thing will keep going as well?
[/quote]

Yeah, the main difference is in separating essence manipulation from spellcasting. Spellcasting is specific learned applications of essence that are categorized under the term of 'spell' as a shorthand, while essence manipulation is a more freeform exchange of essence. Spells are more convenient when on demand in an immediate moment, but more restricted in what they can accomplish by requiring specific combinations of incantations, motions and emotional/conceptual/elemental essence to accomplish. Essence manipulation differs in that it doesn't require incantations or any specific motions - other than the need to physically direct it in some cases - but it takes longer to manifest as a result of not having those additional guidelines to speed up the process. I'll be writing more on the specifics of this in the lore page when I get the chance to, as well. 

What Iraleth did to mend Davil's ribs, for example, would fall closer to essence manipulation - a freeform application channeling the conceptual essence of mending rather than a specific spell. A healing spell appropriate for the task would accomplish that in an instant, whereas it was a longer process through manipulation in exchange for not requiring any words or specific gestures to achieve it.

And yeah, the "cast in reverse" effect would be in play here, for spells that aren't from the primal conduit. Going forward while in this area, characters would find their spells failing unless they're either a primal caster or that they speak their spells backwards; though not every character would necessarily know this right away, depending on their knowledge of leylines or the primal conduit. Ethos activation phrases would still work normally, though.