dnd 5e – Do spells like burning hands specify specific non-material components?

In “Does Burning Hands really require touching thumbs?”, it has been established that burning hands does indeed require touching thumbs. A question that is danced around there is, “is the touching thumbs the somatic component?” This question also extends to spells like dissonant whispers (verbal component) and message (verbal/somatic component).

I’m inclined to think they are, but am unsure. This does have some weird implications if so, like “how loud does one dissonantly whisper?” and “can someone else hear my whispered message?” (I don’t need these answered here; I just include them because they are related, depending on the answer.)