How to turn those additional characters off? After updating to macOS Sierra when I hit a key a little bit longer (it's the same amount of time I always did) i get this and it's constantly disrupting my flow
This "feature" has been around for a few years. See if this helps:
Here's the link:
Here's what you have to do:
Step 1. Go to Terminal (search from Spotlight):
Step 2. Type in this code:
defaults write -g ApplePressAndHoldEnabled -bool false;
Step 3: Logout.