Verbs with two different past tense forms
While many of the most common verbs in English are irregular (e.g. bring, forget), regular verbs far outnumber them. To form their past tenses regular verbs just add -ed or -d to their base form, e.g. talk => talked.
In particular, verbs that derive from nouns follow this regular pattern without exception. Indeed, this pattern is so firmly imprinted in our brains as a basic process for making nouns into verbs that if you were asked to make the invented noun flixxle into a verb you would automatically know how to.
However, there is a very small group of verbs whose past tenses can be either regular or irregular. They include: