Concord refers to grammatical agreement between different parts of a sentence. Some aspects of concord are more difficult for learners to learn than others, for example the third person ‘s'.
In the sentence ‘He doesn't want to go, and now they don't either' there is concord between ‘he' and ‘doesn't' because ‘he' needs an ‘s' on the verb, and between ‘they' and ‘don't'.
In the classroom
Focusing on writing is a useful way for learners to practise concord. Relevant activities include dictogloss, and editing written work in groups.
See also: Dictogloss