Because it doesn't have the local intelligence to understand your unique waveforms that are saying something along the lines of "set a timer for five minutes." Now I'm sure someone could design a specialized device that could act as a voice activated timer--I suspect such exists--but Alexa is a lot more general purpose.
I wonder if it's less that Google Home can't have the local intelligence due to lack of storage/memory/processing, and more that they want to keep it away from their competitors?
Could Google reasonably put their current voice recognition in a small device?
Google is actually working on this. At this year's IO they announced that they are working with silicon manufacturers to include hardware acceleration for their TensorFlow Lite framework. This makes it possible to do on-device speech recognition and natural language processing while keeping the power consumption at acceptable levels.
The evidence would suggest it would be hard. I've played around with various dictation software over the years and it's always been pretty awful. It's only recently with the cloud-based services that it's started to approach usable.
Software that limits itself to specific keywords can absolutely work well. After all, Google and Alexa do it with their wake words. A voice activated timer could be built fairly easily if it hasn't been done already.
General purpose is a lot harder--and then you need the Internet connection for a lot of the queries anyway so there's no real reason to build in local voice recognition if you then can't really do anything useful with it.
I was actually looking at that after I saw this question. PiAUISuite/voicecommand (looks like it can be used with APIs but doesn't need to be) seems to be one and Jasper another. I don't have personal experience with either (yet) but I suspect they're not nearly as good as Alexa/Google Home, especially with a basic microphone. I'm thinking I may play around though.
Thank you for the links. It seems like PiAUISuite uses Google's speech to text (look for the curl call [1]), while Jasper allows choosing between different engines [2]. It has install instructions for PocketSphinx [3] and Julius [4]. Those two seem close to what I have been looking for, although Julius apparently lacks a good model for English at the moment.
