I've longed for this as well. In theory it can be done. The individual ingredients are all available in the universe of FOSS software... speech to text (CMU Sph

I've longed for this as well. In theory it can be done. The individual ingredients are all available in the universe of FOSS software... speech to text (CMU Sphinx, etc), language parsing (NTLK, etc), IoT integration, etc. But assembling all these components and frameworks into an integrated, reliably-working system takes a great deal of time and effort, even if you're a skilled programmer (which I'm not).