Several years ago, I wrote some software that let people who had lost the ability to speak to use a PC or laptop with text-to-speech software. Looking to extend it for some environmental control was my own introduction to X-10. The Lernout & Hausbie scam monopolized all the text-to-speech engines at the time. That and my own failing health made it impossible to continue. Today, there are other relatively low cost methods for text-to-speech.
I did become acquainted with a couple of groups that dealt with issues like this but cannot recall details. And, as most of those I was in touch with had ALS, I doubt any are still around.
Most of the ceiling fans and RF remotes are made by the same company in Taiwan. Adding a remote to an existing fan/light usually involves adding the RF receiver to the fan housing also - it may be a much bigger job than you are anticipating. The frequencies used are documented on my website (although this may not be up to date) and I think I have the RF protocols (I'll just have to find them).
http://davehouston.org/frequency.htmI cannot think of any simple way to accomplish voice control of the RF since the frequency and protocol are different from X-10's frequency and protocol. While there are some Hunter fans that use the same 310MHz frequency, the protocol is certain to be different than X-10's.
If the voice controlled unit that sends RF and IR can be programmed (i.e. to add the fan protocol) it may be possible to hack something together to control the fan. Most RF transmitters of the type used here switch rather slowly so you can feed them an IR code and they will spit it out as RF. Or, it's not too difficult to build a small IR-to-RF repeater that would receive IR and retransmit it as RF.
Can you provide details on the voice controlled RF/IR unit?
Also, everything depends on whether the fan/light is RF-capable. Odds are they are not, based on your description of current operation.