Agreement
Which words change to match another word?
Meaning
Some words change their form to match another word in the same sentence. This can show which words belong together or who or what an action involves. Languages differ in what must match, and some have no such matching rules. Agreement is the matching between words; Endings describes pieces attached to a word, whether they mark agreement or something else.
How to spot it
Change one participant from one to several, or from the speaker to someone else, and check whether any related words must also change.
In your native language
English verbs match the subject in a limited number of forms: most present-tense verbs add -s with he, she or it, and be has forms such as am, is and are. The pointing words this and that go with singular nouns, while these and those go with plural nouns. Adjectives do not change to match a noun.
My neighbor works at a cafe.
The singular subject my neighbor takes works, not work.
This bag is heavy, but these bags are light.
Both the pointing word and the verb change for singular and plural.
In your learning language
Spanish uses agreement: a verb changes to match the subject's person and number. Articles and adjectives match the noun's grammatical gender, its masculine or feminine group, and its number. A past participle such as abierto matches the noun when it describes a state or occurs with ser in a passive sentence, where the subject receives the action, but stays unchanged after haber.
Las tiendas pequeñas cierran a las ocho.
The small stores close at eight.
Las and pequeñas match the feminine plural tiendas, and cierran is plural.
Las ventanas están abiertas.
The windows are open.
Están is plural, and abiertas matches the feminine plural ventanas.
Hemos abierto las ventanas.
We've opened the windows.
Hemos marks the plural subject we; abierto stays unchanged after haber.
Learners whose language leaves adjectives unchanged may mark plural only on the noun and forget the matching article or adjective. Learners whose language changes participles in compound tenses may wrongly change the form after haber.