Expertise

Expertise is an indicator of an entity's attunement to a given Noun. The more Expertise an entity has, the more it can learn and use powerful idioms. As such, every Noun has a separate Expertise value for a given entity, starting at level 0.

For each 2 idioms learned in a Noun, the Expertise in this given Noun increases by 1.

An entity's Wordsmithing Level and Expertise in a Noun both dictate the idioms they can learn and how intensively they can upcast :

In order to learn an idiom with Learning Points, the idiom's Flux Cost needs to be inferior or equal to both the entity's Wordsmithing Level and the associated Noun's Expertise Level. For example, an entity with a Wordsmithing Level of 5, a Fire Expertise of 4 and Water Expertise of 7 can learn idioms of Fire up to a Flux Cost of 4, while it can learn idioms of Water up to a Flux Cost of 5.

Similarly, an entity can only upcast an idiom of a given Noun up to a final Flux Cost inferior or equal to the lowest of either its Wordsmithing Level or the associated Noun's Expertise. For example, an entity with a Wordsmithing Level of 5, a Fire Expertise of 4 and Water Expertise of 7 can upcast its idioms of Fire up to a Flux Cost of 4, while it can upcast its idioms of Water up to a Flux Cost of 5.