quietly vs softly

quietly and softly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
quietly	No	No	No	Yes
softly	No	No	No	Yes

As adverbs, quietly and softly are synonyms defined as:

quietly (adverb)	softly (adverb)
with low volume	with low volume
with little or no sound	with little weight or force
with little or no activity or no agitation (`quiet' is a nonstandard variant for `quietly')	used as a direction in music; to be played relatively softly
in a restful manner	in a manner that is pleasing to the senses