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.