Spelling rules for comparative adjectives:
| Adjective | Comparative | Adjective | Comparative |
|---|---|---|---|
| sad | sadder | slow | slower |
| pretty | prettier | kind | kinder |
| easy | easier | fat | fatter |
| fast | faster | lazy | lazier |
| happy | happier | big | bigger |
| hot | hotter | angry | angrier |
| friendly | friendlier | funny | funnier |
| old | older | quiet | quieter |
| loud | louder | thin | thinner |