There are (al least) three common nouns which a weird plural form (goose, tooth, foot) to (geese, teeth, feet). How dis this come about (language origin?)? Why doesn't foot rhyme with others (compare with boot)?
To lazy to investigate but will take a wild stab that each word was absorbed from a different language with different rules Please Register or Log in to view the hidden image!
You think English has weird rules for plurals, Try Finnish General rule: Add "t" ( this works because so many Finnish words end a vowel) Example: Koira - dog Koirat- dogs However, if the last syllable of the Word has k,p,t,kk,pp, or tt, then the following rules apply K is removed from the word Sika -pig Siat -pigs P becomes V Lupa- permission Luvat - permissions T becomes D Äiti - mom Äidit - moms With the double consonants, you drop one of them Takki - jacket Takit -jackets Noppa- dia Nopat -dice Kettu -fox Ketut -foxes Some words end with "nen", in this case, the "nen" is replaced with "set" Nainen - woman Naiset - women With words ending with "i", its depends on whether is is a "new" or "old" word. An example of a new word: Paperi - paper In which case you use the general rule and add t Paperit -papers With old words, the i is changed to e Meri- sea Meret-seas Siipi -wing Siivet - wings ( note the P to V rule) Old words ending in "si", "si" becomes "de" Vuosi - year Vuodet - years If the word ends in e, add another e Perhe - family Perheet- families (note on double vowels: it doesn't change the vowel sound, you just carry it a bit longer) and these aren't totally inclusive of all the rules, for example Mies - man Miehet - men Poika - boy Pojat - boys To add to the fun, the plural case is also applied to the adjective describing the noun. New room - uusi huone New rooms - uudet huoneet And this doesn't touch on the other cases For example These boys will chase those boys - Nämä pojat jahtaavat noita poikia. With both pojat and poikia being "boys" but one is the subject and the other the object.
It's all about i-mutation in older words. From what I understand, older plurals of words with Germanic origin used to have additional suffixes, and due to laziness in pronunciation (a simplistic description of i-mutation) over hundreds of years, these became shortened. However, a more standard approach became adopted of shoving an s at the end, and newer words tended to follow this rule, but words in more common usage (such as foot / feet) retained their older plurals rather than gradually adopt the -s approach. Some of the older plurals died out in favour of the -s, though. For example, the original words for "friend / friends" would have been friond / friend - with friend being the plural of friond. But over time, due to laziness to maintain that distinction, the words changed due to i-mutation to the ones we know and use today. I say "laziness" - but in a world where there are any number of dialects and accents, differences in pronunciation of vowels could well have caused confusion in understanding, and moving to "rules" that worked regardless of pronunciation may have just been for practical reasons.
The movie "Nell" is a wonderful example of how language may become distorted due to isolation from the larger civilization.