sound

Sound is a linking verb (see here). It is followed by adjectives, not adverbs.

• You sound unhappy. What’s the matter?

Progressive forms are not very common.

• Your idea sounds great. (not Your idea’s sounding great.)

However, progressive forms are possible when there is an idea of change.

• The car sounds / is sounding a bit rough these days.

Sound is often followed by like or as if/though.

• That sounds like James coming up the stairs.
• It sounds as if/though he’s had a hard day.