How come the Plural for Goose is geese but the plural for Mongoose is Mongoose and not Mongeese?

Answer 1

Welcome the the wacky world of English.

There are no rules without exceptions, thats a rule no exceptions.

Answer 2

"Goose" and "mongoose", despite their appearance are entirely related words. The first is ancient (found in Old English), the second a borrowing into MODERN English. Each reflects forms common at the staqe it entered the language.

"Goose" is from Old English -- and like a whole cluster of common Old English/Germanic words its plural form still reflects forms of the word used in Old English. Specifically, when root words added a suffix that started with an i/e-type vowel, the vowel in the preceding syllable would move toward or even become an i/e-type vowel. We know it best from a handful of plural forms, but you can find it in other words as well. (This sort of change to be like a nearby vowel -- called "vowel harmony"-- is a common feature in many languages.) This specific vowel change is called "i-mutation" or "umlaut" (named after the sign used over German vowels to indicate the vowel adds an i/e-shape... the umalut is, in fact, often transferred to English as an e).

Other examples:
man > men (German = Man > Maenner)
mouse > mice (Ger. = Maus > Maeuser), cf. louse > lice
tooth > teeth (Ger. Zahn > Zaehner)
cow > kine (used in the King James Bible) (Ger. = Kuh > Kuehen)
brother > brethren (Ger. Bruder > Bruedern)
old > elder, eldest (Ger. alt > aelter, aeltest)
hale > health
long > length
http://en.wikipedia.org/wiki/Germanic_umlaut
http://www.wmich.edu/medieval/research/rawl/IOE/pronunciation.html#pronounce:imutation

"Mongoose" was borrowed into MODERN English (ca. 1700) from an Indic language. Hence, when we needed to form a plural we simply used the ordinary way of forming plurals in Middle and Modern English, that is, adding an -(e)s.
http://dictionary.reference.com/browse/mongoose

Many words found in Old English did eventually succumb to the 'modern' way of forming plurals -- esp. less common words, but it's nearly impossible to FORCE speakers to apply these changes everywhere, esp to the words they use and know best. (Common words are usually the most irregular in any language. Compare 'irregular verbs' -- come, be, run, etc. are all COMMON verbs.) Thus we have house > houses (though German keeps the old pattern - Haus > Haueser).

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Now about this "that' s just wacky English stuff" --
No, it's not "just English". EVERY language has 'irregularities'. In fact, this whole idea of "rules" is artificial. In many cases WE make up rules to DESCRIBE what typically happens. But the people who speak and develop a language do not sit down and make up sets of rules to rigidly follow! More than that, as languages change and adapt through the centuries, it's difficult to make it all 'stick to the rules'.

And, as you can see from the example of goose/mongoose above, there often IS a very understandable historical explanation. The fact that WE might not know the explanation does not mean there isn't one!

Answer 3

Because that is just the way it is. Both of them are irregular nouns but Mongoose remains the same and Goose when changed to plural has changes in its spelling.