Learn Dutch: De katoenen jas is goedkoper dan de wollen jas. - The cotton coat is cheaper than the woollen coat.

In Dutch, when you want to describe what something is made of, you usually add -en to the material noun to turn it into an adjective. So katoen (cotton) becomes katoenen (made of cotton), and wol (wool) becomes wollen (woollen / made of wool).

Why does wollen have two 'l's when the base word wol only has one?

This happens because of the Dutch spelling rules for keeping vowels short. The 'o' in wol is a short vowel. When we add the -en ending, we have to double the consonant (the 'l') to keep that short 'o' sound. If we only wrote one 'l' (wolen), it would be pronounced with a long 'o' sound.

Normal adjectives usually get an extra -e ending with de words (like de mooie jas). Why don't these?

Material adjectives ending in -en are a special exception! They are fixed and never change. Whether the noun is a de word or a het word, the adjective stays exactly the same (katoenen, wollen). You never add an extra -e to them.

Why is goedkoper (cheaper) spelled with only one 'o', while the base word goedkoop (cheap) has two?