At Lenovo's IFA 2017 briefing today, the company has announced an answer to that as well with the Home Assistant Pack. It attaches to the Tab 4 8, Tab 4 8 Plus, Tab 4 10, or Tab 4 10 Plus, and turns the device into an Alexa-powered smart speaker with a screen. You can ask it to show you the weather, set a timer, turn on your lights, and much more.
With far-field voice technology of up to three meters, you should be able to call out to it from anywhere in the room. It uses Lenovo's Home Assistant app on the tablet itself, although to configure some features of the voice assistant, you'll need Amazon's Alexa app.
The Home Assistant will be available beginning in October, starting at $69.99. The Tab 4 series of tablets is already available from Lenovo.com and the company's partners.