Question

Do all irregular verbs make their past forms using the same pattern? Can an irregular verb's past and past participle forms be different from one another?

Answer 1

No, they do not. If there was a single pattern to create past forms of all verbs they would not be called irregular.

Explanation:

All irregular verbs can be divided in 3 groups:

1. Verbs with all 3 different forms : go - went - gone, see - saw - seen etc.
2. Verbs with identical Past Simple and Past Participle forms: loose - lost - lost, send - sent - sent, learn - learnt - learnt etc.
3. Verbs with all identical forms: cost - cost - cost, hurt - hurt - hurt, cut - cut - cut, etc.

Note Verb learn is irregular in British English, in American English it is a regular verb learn - learned - learned.