Actor / Source
Who or what starts the event?
Meaning
The participant that acts, causes, initiates, controls, or is presented as the source of an event.
How to spot it
Ask who is doing, causing, or starting the event.
Examples
I|Peter|the dog|the machine|the wind
the teacher explains|the wind opens
The dog bit the postman.
Visual guide
ACTOR / SOURCE who starts the event? [the dog] -> bit -> postman [the wind] -> opens [the teacher] -> explains = doer/causer/source
Actor clues may differ order: [dog] bit postman case: [dog-NOM/ERG] agreement: dog -> verb pronoun form: I / me topic: [dog-TOP] voice: by [dog] role = event starter
Language View
In your native language
In basic English clauses, the actor is usually before the verb and can trigger subject-verb agreement.
She opened the door.
she = the actor/source
In your learning language
The actor is often recoverable from verb agreement, so subject pronouns are frequently omitted unless needed for emphasis or contrast.
María prepara café.
María prepares coffee = María is the actor
Learners may overuse subject pronouns or miss that the verb ending already identifies the actor.
Same block, different coding
Both languages use this block strongly, but they signal it differently. Focus on form changes, not only meaning.