Irregular verbs are verbs that do not follow the standard pattern of conjugation in the past tense or past participle forms. Unlike regular verbs, which typically add "-ed" to form these tenses, irregular verbs change their spelling in unique ways. For example, the verb go becomes went in the past tense, and have changes to had. These verbs are essential in the English language, as they are commonly used in everyday conversation and writing. Learning irregular verbs is important for achieving fluency, as they often appear in both spoken and written forms. Mastering them helps improve overall communication skills.