How to add suffixes to words ending in -fer

When do you double the r?

Add your suffix and say the word aloud.

If the -fer is still stressed then double the r, like preferred.

If the -fer is no longer stressed then leave it as a single r, like preferable.

Prefixes and suffixes, there's more to learn...

This guide
three monsters making a cake

How to add suffixes to words ending in -fer