Does it have to be audio? A meshtastic radio like what you get from https://www.lilygo.cc/collections/lora-or-gps will pair to a smartphone app (or browser app) and let you text with people who also have a meshtastic radio nearby. If you're in a reasonably dense area there may be several people chatting.
How old are we talking? If the CPU is >10 years old and/or some kind of ARM, it may not have hardware encryption acceleration, which means it'll happen in software. I did that once, it was horrible. lscpu |grep -i aes should probably tell you what you need to know.
When I was a kid, we had a single family home in a major city. Amazing being able to walk or take transit everywhere but also not share walls and to have a back yard. That crappy little house is totally unaffordable to me now.
Does it have to be audio? A meshtastic radio like what you get from https://www.lilygo.cc/collections/lora-or-gps will pair to a smartphone app (or browser app) and let you text with people who also have a meshtastic radio nearby. If you're in a reasonably dense area there may be several people chatting.