To pluralize a noun, we usually add an -s to the word. Sometimes, we may even add an -es. For example, we’ll say:
Yet, we come across weird plural words such as “children” and “oxen,” rather than “childs” and “oxes.”
The reason in a nutshell is that, way back when, English had two competing plural suffixes: -s and -en.
According to the Oxford English Dictionary (also known as the OED and the bible on English words), “children” began life in Old English (before 1100 AD) as “cild.” For those interested, Beowulf was written in Old English. In the twilight years of Old English, you got to say (because really, what were the chances you could write?!) “cildru” and “cildra.”
By the time Middle English rolled around (think Chaucer’s Canterbury Tales, around 1100-1500 AD), there were two primary competing versions: “childe” and “childre/childer.” The latter examples were offspring of Old English’s “cildru” and “cildra.”
Unfortunately, “childe” (some haughty Middle English deviant form!) was rarely used compared to the “childre/childer” combo (back then, spelling didn’t count all that much).The under-represented “childe” form eventually got pushed out by speakers and people just used the “childre/childer” version instead.
Around the 12th and 13th centuries, people started to use the -en suffix in order to make things plural. So even though “childre/childer” was already a plural form, people just tacked the -en suffix onto it anyhow.
Funnily enough, words and their associated bits seem to be in a perpetual battle for supremacy. “Children” beat out a lot of competitors to be where it is.
The competing -s suffix that tags onto most nouns today has won over most of the English language, save for your irregular plurals such as poor old “children.”
One reason why we have yet to switch over to “childs” is because unlike “brethern” (RIP) — a basically archaic plural form of “brother,” we use “children” so often. Words that we use a lot are most resistant to change. After all, hearing “childs” is just weird. If you say it, you’ll probably be corrected.
Not to say that “children” is here to stay. Who knows! Maybe in 100 or 200 years, people will look back and say “Those 2009 people spoke funny. Why would they use ‘children’ when ‘childs’ makes the most sense? It fits everything else!”
Poor “children,” dead word walking…