Recording dialogue in the wilderness

Audacity can display a recording as a multi-coloured spectrogram , rather than a waveform …


http://manual.audacityteam.org/o/man/track_drop_down_menu.html

If you must have a real-time spectrogram : one which responds instantly to sounds picked up by a microphone, (which I don’t think will be of any use to you), you can get a free one for Windows computers here … Filtering frequency during recording - #12 by Trebor