Disable Mac typing Accent Menu In Mac OS 10.12 , if I hold down the key, a menu of blue letters with accents and diacritical marks appears.  Prior behavior was to enter a string of the letter pressed lke thiiiiiis.  How do I disable this menu so I can type many of the same letter?

Open a Terminal window and run defaults write -g ApplePressAndHoldEnabled -bool false. Some programs will reflect the new setting immediately, but you may need to restart programs like Slack in order to get them to load the setting.
This Answer is from http://osxdaily.com/2011/08/04/enable-key-repeat-mac-os-x-lion/ .
Related Superuser content at after holding a key for a while I can't type until i close and re-open the app .