We’ll begin with box,
the plural is boxes
But the plural of ox is oxen,
not oxes.
One fowl is a goose,
but two are called geese.
Yet the plural of mouse is
never meece.
You may find a lone mouse,
or a whole post of mice.
But the plural of house is 
houses, not hice.

If the plural of man is 
always men,
Why shouldn’t the plural of
pan be pen?
If  I speak of a foot and you
show me two feet -
If I give you a boot, would
the pair be called beet?
If one is a tooth and the
whole set are teeth,
Why shouldn’t the plural 
be called beeth?

If the singular’s this, and
the plural these,
Should the plural of kiss
ever be keese?
We speak of a brother and
also brethren,
But though we say mother,
we never say methren.
Then the masculine
pronouns are he, his and
him.
But imagine the feminine,
she, shis and shim!