A:AnswerWe are currently working to add more setting on our models, but this TV does not have this feature yet. For more information regarding this TV's setting, please contact us at 877-467-4289. Viri E. Toshiba Support
A:AnswerNo, you can't set the sleep timer using your voice.
To see a list of Alexa commands you can use to control your TV, please visit:
https://www.amazon.com/gp/help/customer/display.html?nodeId=202174250
David M. - Toshiba Support