“Specifically with emacs style character manipulation modifiers -- alt-b and alt-f. In older versions of OS X -- I think pre snow leopard although I can't remem

“Specifically with emacs style character manipulation modifiers -- alt-b and alt-f. In older versions of OS X -- I think pre snow leopard although I can't remember the exact version which first included the change -- the alt-b and alt-f characters were bound by default system wide (I think this mechanism is part of CoreText maybe?) to emacs style forward-word and backward-word. At some point OS X changed to turn all these alt-key combos into Unicode characters for the given keyboard language. This made the forward word and backward word behavior no longer available system wide at all text editing points.” I don’t believe that was ever the case. ⌥B and ⌥F were never bound to an Emacs-style forward-word and backward-word, even back in the pre-Leopard days (from what I remember). You may be confusing it with ⎈B and ⎈F (⌃B and ⌃F), which move backwards and forwards by one ‘character’, respectively, and still work even on the newest versions of macOS. If you actually do want to move between words, then the keyboard shortcuts ⌥← and ⌥→ have always done that, and work across every app that uses Cocoa text fields.