Read the article; the -en in this particular case arose after the loss of the case system, in a hypercorrection during a period when -en and -s were the two main plural endings.
I did, I was speaking about -en vs -n. Why -en for children and not just -n. Have I missed something?
Plain -n isn't used anywhere in English that I know of for a plural; the consonant cluster childrn would be improbable.
Re:Why “children,” not “childs”? (2016)
by _emacsomancer_ on Sunday May 27, 2018 @09:36PM
(#17170140)
It doesn't come from German; both English and German inherit it from Proto-Germanic.
https://en.wiktionary.org/wiki/-en#Etymology_2