This is kinda funny in light of the idiocy in this thread ...
If the plural of "goose" is "geese", then why don't we say the plural of "moose" as "meese"? Also, with hippopotamus, why isn't that hippopotami? Cactus is cacti.
Related:
meese
lol
Let me pull an answer out of the ...
*ANSWERBAG*
Goose comes from German, and in German it often happens that an OO in the root becomes an EE in the plural--goose,
geese; foot, feet. (The reason is that the plural ending in German is also an E sound, and it's easier to say EE-E than OO-E.)
The moose, however, is an American animal so it doesn't follow the German pattern. And the mongoose is an Asian animal so it doesn't either--plural of mongoose is "mongooses."
In an environment where everyone knows Latin or Greek, people DO say hippopotami, but since most people don't these days, it makes you sound like a stuffed shirt.
Most of the irregularities in English come from the fact that virtually all of our words were borrowed from other languages with different rules for things like how to form plurals.