Actant semantics: Subject Semantics (SUS), Actant 1 Semantics (A1S), and Actant 2 Semantics (A2S)

Subject Semantics (SUS), Actant 1 Semantics (A1S), and Actant 2 Semantics (A2S) are Relations each of which connects an Action to one or more Concepts describing semantically the role of the holder of the actant slot. E.g., A "to speak (to sb - about st/sb)" would have the SUS: C "speaker",  A1S: C "participant in a conversation", and A2S: C "speech content".

These Relations describing actant semantics then allow to study the roles of entities holding that actant slot. E.g., we can inspect all women who have either the in-statement CLA C "preacher", or who are known to have A "preached", because A "preach" would have exactly the SUS: C "preacher". Therefore, the actant semantics enrich actant role holders with the respective roles implied by the Action.

These relations also allow to properly understand the direction of action: e.g., a text can say that P Lucy - A listened - (to) P Mary, or that P Mary - A spoke - (to) P Lucy. The relevant actant semantics will allow to identify, in both wordings, Mary as the speaker and Lucy as the listener. Thus, for research purposes, we can for instance safely produce a directed conversation tie going from Mary to Lucy rather than the other way round from any of the two wordings, and also harbour the passive and active voice correctly under the same roof.

Actant semantics are the CASTEMO way of ensuring semantic role labelling: it is done by properly defining any Action type's semantic valency, rather than losing time with labelling semantic roles in specific Statements.