I run the R&D lab here at NAR (
crtlabs.org). We research and do development around the smart home, smart city, IoT, energy, renewables, etc.
Voice control is extremely popular for smart home control, and privacy is a big issue for us, so we're just investigating the different offerings.
As for Elixir, I've just started using it, and I really love it. There's a great project called Nerves, still very young, that enables Erlang/Elixir on embedded devices. The goal is to use that, for a small home voice controller.
We are also working on an indoor air quality monitor, and the backend is in Elixir.