I think my main issue is with your choice of the word "pattern", as something you can match against .... Because the patterns are sometimes the entire word (lower vs. tower, cough vs dough). That's not the meaning I usually associate with pattern (in the context of pattern matching).

If you had used "classes", I probably wouldn't have bothered responding in the first place... "cough" falls in the same class "rough", and "dough" does not. And those classes each match a terser pattern ("ough"). But having matches the terser pattern, you are not better off knowing how to pronounce it than knowing the entire word.

Thanks for an interesting discussion, and cheers !