Sound is not an priority, Natron is not a NLE. You can however use the AudioCurve node (will be available in a future Natron release) to generate curve data for use in Natron. I will also look into JACK integration at some point, but there are more important things to work on the moment.
Natron is a community project with very limited resources, so feature requests has a low priority. You are more or less depending on that one of the developers want the feature, else it will probably not be worked on.