In many languages one word’s form depends on another’s. Agreement is the requirement that certain words share features such as person, number, gender, or case.

English still shows subject-verb agreement: she walks versus they walk. Richer systems mark adjectives and determiners to match nouns, or make verbs agree with more than one argument. Failed agreement makes a sentence sound unfinished or non-native.

Agreement helps listeners track participants in complex clauses. Acquisition research watches children master these dependencies. Typologists classify languages by how much agreement they demand and which features participate.

• Matching of grammatical features across words
• Often involves person, number, and gender
• Links verbs to subjects and modifiers to nouns
• Varies greatly in richness across languages