A player asked whether learning True Names is one to one with the capability to use them, and whether one could instead recite a True Name from a book as they're casting without ever truly memorising it.
You mean True Name as in ArMDE p.445 True Names and Synthemata?
Then you read there:
Each True Name is a spelllike ability recorded as "True Name of (Being)"
on the character sheet, and costs 5 experience points to learn. These points can come from Practice, Exposure, or Adventure; or from an Advancement Total dedicated to the appropriate (Realm) Lore. You receive one free experience point in the (Realm) Lore whenever the character learns a True Name completely.
That unfortunately doesn't answer my question.
I know learning a True Name requires 5xp- I am asking about using a True Name without learning it such as reciting it from a book the character has on hand.
Note, that "Each True Name is a spelllike ability recorded as "True Name of (Being)" on the character sheet, and costs 5 experience points to learn." A p.445 True Name is not just a sequence of words in a book to read aloud.
Does that help? Or where is the problem?
It may well be, that you look for quite another kind of True Name than the one used to affect Daimons in ArMDE.
In your saga, you might have specific rules to read Names of Power from casting tablets. These might work with the TMRE p.76f Names of Power Minor Hermetic Mystery Virtue, where the Names of Power require Mystery Initiations, but work like Muto Vim spells providing a casting bonus equal to their magnitude.
The interpretation that I've used, without 'training and expertise', you cannot properly invoke a True Name.
I see. I always understood it to be so, hence why grimoires can be a source of information- seems I was wrong. Thank you.
My personal view is that a True Name also encompasses a deeper understanding of the spiritual nature of the spirit in question, and the associated sympathies/associations of the spirit. This deeper understanding is employed in subtle ways (proper associations, mindset/emotional state, proper techniques to be employed with the Penetration ability etc.) that are essential to properly using any True Name. Knowing the verbal/spoken name is only a small visible part of actually understanding the deeper nature of a spirit and using it in magic.
To nitpick, sahirs do have True Names in summoning spells without needing to learn the True Name themselves. Although that requires another sahir to invent that spell.