I propose adding functionality to NVDA to add the ability to report indents as tones.
My design ideas are based off of my indentone add-on at
https://github.com/derekriemer/nvda-indentone
Make NVDA report indents as tones when the user selects this option. This option might be in document formatting. We'd need to enable several new items if report indents is enabled that controls report indents .

• Report indents with speech check box.
• Report indents with increasing pitch checkbox.
• Use stereo to indicate indent level.
• (one of these proposals): Indent space behavior combo box with:
  • one quarter tone pitch increase per space.
  • One whole tone pitch increase for each n spaces.
  • If the later one there is selected, we need an edit control to specify what N is. We need to figure out better language to specify here.
• or: just an edit control asking how many spaces equals one tab. Then, one tab is one whole tone, and any sub part gets subdivided.

The code design of my current add-on monkeyPatches speech.getIndentationSpeech to do this. I'd probably put most of this code there, and maybe put a tones.reportIndentation item in tones.py so that I don't bloat the speech.getIndentationSpeech function with unnecessary math and stuff. We could just use beep inside tones in that case. As for getting config values, is it fine performance wise to just use config.conf["documentFormatting"]["reportIndentsAsStereo"] for this or is that too slow?