Concord agreement in English refers to the grammatical rule that ensures subject-verb agreement in a sentence. This means that the subject and the verb in a sentence should agree in terms of number and person. Failure to follow this rule could result in incorrect and confusing sentences.

For instance, if the subject is singular, the verb should be singular as well. Similarly, if the subject is plural, the verb should also be plural. Here’s an example:

Incorrect: The cat on the table look happy.

Correct: The cat on the table looks happy.

In the incorrect sentence, the subject and the verb do not agree in terms of number. The subject is singular while the verb is plural. The correct sentence, however, follows the concord agreement rule by making the subject and the verb agree in number.

Another example is:

Incorrect: The team have won the game.

Correct: The team has won the game.

In the incorrect sentence, the verb ‘have’ is used to describe a singular subject ‘team’. The correct sentence, which follows the concord agreement rule, uses ‘has’ to agree with the singular subject ‘team’.

The concord agreement rule applies not only to simple sentences but also to compound and complex sentences. For instance:

Incorrect: Neither the teacher nor the students were interested in the topic.

Correct: Neither the teacher nor the students was interested in the topic.

In the incorrect sentence, the verb ‘were’ is used to describe the singular subjects ‘teacher’ and ‘students’. The correct sentence, however, follows the concord agreement rule by using the singular verb ‘was’ to agree with the singular subjects.

In conclusion, concord agreement is an essential grammatical rule in English that ensures subject-verb agreement in a sentence. Writers and speakers should always ensure that their sentences follow this rule to avoid confusion and incorrect sentences. A good understanding of concord agreement will improve your writing and communication skills, making you a more effective communicator.