In this podcast, David Woodbridge demonstrates how in watchOS 3 you can select one or more Complications to be spoken when you wake your Watch. Simply touch the complication, swipe up to “Enable Auto Speak," and double-tap. Repeat for any Complications you want. When you tap your Watch, it will now speak the time, followed by the complication(s) you've set to be auto-spoken. Use the same process to turn the feature off.