Faldage, this is interesting. How far back would we go to see 'to teach' identified as a regular verb?

And what would be examples of the strong (irregular) verbs? To be? Would these be the verbs that completely change form? How many are there?

The verb endings changing, seem to me, completely regular. But when I begin to show the conjugation process, I want to keep it simple as possible, so will introduce some verbs that are quite easy to conjugate. Then I'll move on to what I consider to be regular verbs in which spelling rules dictate some slight changes, such as in 'to change.' After we've covered those, I'll move on to what I think of as being irregular verbs--but, wow!, to read here from you that 'to teach' has been classified as regular is quite a surprise.

Anyway, if you care to write anything else about this topic, I would be very interested in learning more.