Short and shortly
Short is used as an adverb in expressions like stop short (= stop suddenly) and cut short (= interrupt)
Shortly means ‘soon’.
- You will hear from us shortly.
Slow and slowly
Slow is an adjective; slowly is an adverb. However, slow can be used as an adverb after verbs like go and drive.
- Go slow.
Sound and soundly
Sound is used as an adverb in a few expressions. Example: sound asleep.
- The baby is sound asleep.
In other cases we usually use soundly.
- The baby is sleeping soundly.
Straight is used both as an adjective and as an adverb.
- A straight road goes straight from one place to another.
Tight and tightly
Tight is an adjective; tightly is an adverb. After certain verbs, tight can also be used as an adverb.
Common expressions are: hold tight and packed tight. Note that before a verb, we always use tightly.
Wrong and wrongly
The normal adverb is wrongly. In an informal style, wrong can be used instead of wrongly after a verb.
- I wrongly believed that I was going in the right direction.
- You guessed wrong.