What is grammatical deviation in English?

Grammatical deviation refers to breaking the constant relationship between signifier and signified, which leads to its deviation from the established rules in sentence pattern, tense and word order, forcing readers to experience the aesthetic information loaded in poetry in a special perspective and way.

In English poetry, grammatical deviation is mainly manifested in vague reference, disordered word order and incomplete sentence structure. But it often brings unexpected happiness to readers. For example, Dylan Marles Thomas's poem A Sad Thing is a grammatical deviation.

The importance of English grammar;

Grammar is the foundation of language learning. Grammar is a rule that plays an organizational role. Knowing grammar can solve the problem of insufficient sense of language or vocabulary in reading.

2. Grammar is the basis of language use. Grammar has a historical and civilized background, but in daily use, especially in oral English, the grammar of people's language is not rigorous. In some important written or formal oral communication occasions, the authority of grammar provides the guidelines for use.