Irregular verbs are verbs that do not follow the normal patterns for tense and past participle. While most English regular verbs use the ending “-ed” for the past tense and participle forms, irregular verbs each have their own unique tense forms and past participles.
Irregular verbs are one of the hardest parts of the modern English language because they’re all a little different. Since there’s no formula, English speakers have no choice but to memorize each one, along with their special verb forms.