A subject is a grammatical relation that exhibits certain independent syntactic properties, such as the following:

• The grammatical characteristics of the agent of typically transitive verbs
• The grammatical characteristics of the single argument of intransitive verbs
• A particular case marking or clause position
• The conditioning of an agreement affix on the verb
• The capability of being obligatorily or optionally deleted in certain grammatical constructions, such as the following clauses:​
  • Adverbial
  • Complement
  • Coordinate
• The conditioning of same subject markers and different subject markers in switch-reference systems
• The capability of coreference with reflexive pronouns

The identification of the subject relation may be further confirmed by finding significant overlap with similar subject relations previously established in other languages. This may be done by analyzing correspondence between translation equivalents.