With the most number of irregularities and exceptions to rules, let's see how well you know English. Here is an excerpt of a poem by an unknown author about how complex the English Language is.

The English Lesson (excerpt)

We’ll begin with box, and the plural is boxes,
But the plural of ox should be oxen, not oxes.
Then one fowl is goose, but two are called geese,
Yet the plural of moose should never be meese.
You may find a lone mouse or a whole lot of mice,
But the plural of house is houses, not hice.

If the plural of man is always called men,
Why shouldn’t the plural of pan be pen?
The cow in the plural may be cows or kine,
But the plural of vow is vows, not vine.
And I speak of a foot, and you show me your feet,
But I give a boot… would a pair be beet?
If one is a tooth, and a whole set is teeth,
Why shouldn’t the plural of booth be beeth?

If the singular is this, and the plural is these,
Why shouldn’t the plural of kiss be kese?
Then one may be that, and three be those,
Yet the plural of hat would never be hose.
We speak of a brother, and also of brethren,
But though we say mother, we never say methren.

I take it you already know
of tough, and bough and cough and dough?
Others may stumble, but not you
on hiccough, through, slough and though.
Well done! And now you wish, perhaps
To learn of less familiar traps?
Beware of heard, a dreadful word
That looks like beard and sounds like bird.
And dead; it’s said like bed, not bead!
For goodness sake, don’t call it deed!

And do and go, then thwart and cart.
Come, come, I’ve hardly made a start.
A dreadful language: Why, man alive,
I’d learned to talk when I was five.
And yet to write it, the more I tried,
I hadn’t learned it at fifty-five. 

If you understood some or most of what the poem meant then kudos to you! For despite the difficulties and irregularities, you were able to understand this crazy, crazy, language.