What are the rules for forming comparative and superlative degrees of three or more syllable adjectives?

What are the rules for forming comparative and superlative degrees of three or more syllable adjectives?

The rules for forming comparative and superlative degrees of three or more syllable adjectives are as follows:

1. Comparative degree:
- Add the word "more" before the adjective to form the comparative degree.
Example: more beautiful, more intelligent

2. Superlative degree:
- Add the word "most" before the adjective to form the superlative degree.
Example: most beautiful, most intelligent

Note: Some three or more syllable adjectives can also form the comparative and superlative degrees by adding the suffixes "-er" and "-est" respectively, but this is less common.
Example: happier (comparative), happiest (superlative)