Google Chrome	70.0.3511.0 (Official Build) canary (64-bit)
Firmware Version	Google_Eve.9584.160.0

Steps to reproduce:
# Turn on Select To Speak using Settings> Accessibility 
# Fold into tablet or only use touchscreen
# Tap button, select text to start reading
# Tap on an edit text area to bring up onscreen keyboard
Expected: some way to stop speech
Actual: since onscreen keyboard blocks the STS button, you'd have to collapse it to get to the button to stop speech

An onscreen way to silence speech would alleviate this bug, I filed a feature request for a two finger double tap to silence like ChromeVox: https://bugs.chromium.org/p/chromium/issues/detail?id=867530