Correct Pronunciation

[calvin]

I agree. But, isn't straight past tense for "to build", was built? So what is your point?

I'm confused about what you are trying to get across.

Please don't take it the wrong way, I'm just pointing out that at the same time that you wrote that the participle must be "spelt" [ie it's irregular], you used the participle for "spell" as a regular verb. I could of course be wrong but I think this is passive with a modal verb, so using the participle.

Basically, if "to spell" [used with this meaning, not the other you mentioned] were always irregular, there would be no "spelled" [with that meaning] just as there is no "builded" - it would be "it should be spelt...", just as it's "it should be built..."

"To spell" as an irregular verb is [spell / spelt / spelt], as a regular verb it's [spell / spelled / spelled].