"Kamer" is apparently a cognate to the English imported word "chamber," from Latin.
Why is the plural for 'markt' -> 'markten' and the plural for 'kamer' -> 'kamers' instead of 'en' ending? Is there any rule behind this?
I'm sure you can look it up around here too, on the plural(s) lesson
the sound of the word itself, and how it would sound as a plural is responsible for it
Nouns consisting of multiple syllables, which end with -er, -el, -em, -en, -erd; often those with -aar und -aard too.. which don't have that last syllable STRESSED, get an -s as a plural
most Dutch words have -en however
also regard how consonants can change or double.. just like vowels can decrease
it's basically a phonetic thing