Verbs ending in -en

There are a small number of verbs made from adjectives . We add -en as suffix to an adjective to make something more of that quality the adjective describes.

Lenghten = to make long
Harden= to make hard
Sharpen= to make sharp
Sweeten= to make sweet

They've made great effort to lessen the noise of planes. =
They've made great effort to make the noise of planes less.

Yesterday's hurricane flattened several houses in the area. =
Yesterday's hurricane made several houses in the area flat.

These verbs fall into certain categories:

· Dimensions and shape - lengthen, shorten, broaden, largen, straighten etc
· Light and colour - brighten, darken, whiten, pinken, blacken etc
· Density and composition - harden, soften, thicken, densen etc
· Others - freshen, ripen, sharpen, sweeten etc

These are ergative verbs. It means they can be transitive or intransitive, and the object of the transitive verb becomes the subject of the intransitive verb.

· The hot summer ripened the fruit earlier than usual.
   The fruit ripened in the sun.

· You madden me when you talk of my ex-wife!
   I madden when you talk of my ex-wife!

· local government is widening our road at the moment.
  The local government is making / getting  our road wide at the moment.