There are three degrees of comparison in adverbs – the Positive, the Comparative, and the Superlative. The adverbs form their comparatives and superlatives using –er and –est , and more and most. Adverbs that end in –ly use the words more and most to form their comparatives and superlatives.

The one-syllable adverbs use ‘-er’ in the comparative form, and ‘-est’ in the superlative form.

Adverbs which end in ‘-ly’ or have three or more syllables each form the comparative with ‘more’ and the superlative with ‘most’.

The comparative form is used to compare two things.

• We must not reach there later than 7 o’clock.
• You speak more loudly than a loudspeaker.
• Sirius shines more brightly than all the other stars.

The superlative form is used to compare three or more things.

• He arrived the earliest, so he had to wait for the others.
• Why do you have to speak the most loudly of all at the meeting?
• Of all the girls, your sister sang the most sweetly.

It is not correct to use –er and more together, or –est and most together.

• The tree is more taller than the giraffe. (Incorrect)
  The tree is taller than the giraffe. (Correct)
• This turkey is the most oldest in the farm. (Incorrect)
  This turkey is the oldest in the farm. (Correct)

Some adverbs form the comparative and the superlative irregularly.

• Of the two teddy bears, which do you like better?
• This has to be the farthest I have ever walked in my life.

(For more on comparison of adverbs using more and most, see List 8)