The macOS “say” utility does not work for non-root users in Sierra

Solution 1:

It was a compatibility issue with tmux. Works as expected outside of tmux sessions.

Solution 2:

Make sure the reattach-to-user-namespace program installed and add lines like the following to your ~/.tmux.conf, when you run "say" utility inside of a tmux session.

brew install reattach-to-user-namespace

# In .tmux.conf:
set-option -g default-command "reattach-to-user-namespace -l zsh"

# To kill your existing tmux server (and everything running “inside” it!):
tmux kill-server

Some useful links:
1. Mac "say" not working in tmux session - https://github.com/tmux/tmux/issues/716
2. tmux-MacOSX-pasteboard - https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard