Speech-act participant (abbreviated SAP) refers to 1st or 2nd person to the exclusion of 3rd person.
Certain subsystems of a language’s grammar are sensitive to speech-act participants. (They do not distinguish between 1st or 2nd person, but contrast them both with third person (non-speech-act participant).)
|The man saw me.|
|The man saw you.|
If the object is not a speech-act participant, the 3rd person noun may not be marked by ergative case:
|The man saw the child.|
|(*ɨwínš-nɨm i-q̓ínun-a miyánaš-na)|
In some literature (e.g. Andrews 1985), the term local is used for the speech-act participant.
Andrews, Avery. 1985. The major functions of the noun phrase. In Language Typology and syntactic description, vol. 1. Clause structure, ed. by Timothy Shopen, pp. 62–154
Rude, Noel. 1997. On the history of nominal case in Sahaptian. In International Journal of American Linguistics, Vol. 63, No. 1. University of Chicago Press, pp. 113–143