Comment by lambdaone
You could just about squeeze voice down LoRa with a really low-bandwidth codec, as really aggressive codecs can manage < 0.5 kbps. If you want to sacrifice voice quality but use standard codecs, the military MELPe codec has 600 bits/s as one of its standard modes.
And yet such implementation never was seen outdoors.
Because it would likely violate the restrictions setup for the LoRa frequency. Using a normal walkie-talkie has none of those limitations while being cheaper and more versatile.