If it's something that takes a fixed amount of time I'll usually just set a timer on my phone

Consider…

<ctrl><space> invokes Quicksilver.app
. enters text mode
<message>
<tab> to action pane
Large Type
<ctrl><enter> to make a compound object
Run after Delay… or Run at Time…

… and Quicksilver.app does this very nicely without your fingers ever leaving the keyboard (if you're making tea… your fingers probably already left the keyboard).

Consider also

<ctrl><space> invokes Quicksilver.app
. enters text mode
<message>
<tab> to action pane
Speak Text (Say)
…

(These suggestions live in mac land. If you live in Windows land, consider moving. If you live in Linux land you'll probably figure our how to do this yourself pretty quickly :)