Semantic roles, also known as thematic roles or theta roles, are a linguistic concept used to describe the relationship between verbs and their arguments in a sentence. These roles help to identify the different functions that nouns, pronouns, and other noun phrases serve with respect to the action or state expressed by the verb.
Common semantic roles include:
1. Agent: The entity that performs the action expressed by the verb.
2. Patient: The entity that undergoes the action or is affected by it.
3. Theme: The entity that the action or state applies to.
4. Experiencer: The entity that experiences a certain sensation or feeling.
5. Instrument: The means by which the action is carried out.
6. Location: The place where the action occurs.
These roles help to organize the participants in an event or state described by a verb, and they play a crucial role in understanding the meaning of sentences. Semantic roles are essential for linguistic analysis, natural language processing, and understanding the relationships between different elements in a sentence.