Some irregular plural nouns do have a double vowel like goose/geese and foot/feet. Some are irregular in other ways. For example other nouns change the vowel sound in the plural, but by adding a double vowel (man/men, mouse/mice). A few nouns still have their Old English plurals (ox/oxen and child/children) while still other nouns don't change from singular to plural (sheep/sheep, fish/fish); there are even a few nouns that use a plural form for the singular (headquarters/headquarters, species/species)!
Irregular Noun Plurals has a more complete comprehensive list of irregular nouns.
I hope that helps.
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