- He can speak English fairly well.
Fairly does not suggest a very high degree.
- ‘How was the film?’ ‘Fairly good.’ (Not the best one I have seen this year.)
Quite
Quite suggests a higher degree than fairly.
- ‘How was the film?’ ‘Quite good.’ (You ought to watch it.)
Quite can modify adjectives, adverbs, verbs and nouns.
- She speaks English quite well.
- He is quite tall.
- He is quite a scholar.
- I quite enjoyed myself at the party.
Rather
Rather is stronger than quite. It suggests ideas such as more than is usual, more than was expected or more than was wanted.
- I think I should close the window. It is rather cold.
- Do you see that rather tall boy standing over there.
- ‘How was the film?’ ‘Rather good.’ (I was surprised.)
Rather can modify adjectives, adverbs, verbs and nouns.
- It was rather a success.
- I rather think we are going to lose.
Pretty
Pretty is similar to rather.
- She is a pretty good girl.
- ‘How is things?’ ‘Pretty good.’
Pretty can modify adjectives and adverbs. It can’t modify nouns or verbs.
In the example above for “pretty” it says “How is things?”
It should be “How ARE things?” since thing is plural. Correct me if I’m wrong.
How is things is alright in an informal style.