Help with adverbs' rules

[Ismahan Noura]

Hello ,

As far as the adverbs are concerned, I read that we should add an “l+y” for all the adjectives that end with « able » or « ible » , like: changeable = changeably . But why in this word we don’t double the “L” ?! is it an exception !

[Rover_KE]

We double the L when the word ends in L — real>really; normal > normally.

Changeable doesn't end in L.

Rover