Could this not mean "The tone is not helpful" - i.e. you don't like someone's tone of voice?
Yes. It could also mean "The clay is not helpful" or "The shade is not helpful". Clay in this context would only be the stuff used in modelling, but not what you'd possibly find in a riverbed (that's Lehm). And with shade I mean shade of a color.
I would read it that way without any context.
I thought this was commentary on some of Duolingo's audio.
The first translation to this word was clay. The second was sound. I don't see the connection.
Its a homonym. There is no connection.
Also they have different plurals: tones = Töne, clays = Tone.
It would be better to change these meaningless sentences like this one.
It won't help you to learn the language.
Why not 'The sound isn't helping'?