Diphthongs?

Goddamnit no--The "o" of "goat," and the "a" of "gate," are NOT diphthongs in Standard American and Canadian English, but, rather, monophthongs, like the monophthongs 'o' and 'e' of Spanish and Italian--and, as it happens, as the vowels in "goat" and "gate" were pronounced everywhere, even in southern England, in the first three-quarters of the 18th century. We do not say "go-oot," or "gay-eat."