TapNoiseIf one key feels different or fails in every app, investigate the keyboard itself. If many keys behave strangely without a physical change, inspect input settings before assuming hardware damage.
Narrow down the symptom
Test the key in TextEdit and another local app with harmless text. Confirm the input source. Check Slow Keys if short presses seem ignored, and Mouse Keys if letters move the pointer instead of typing.
An external keyboard can help separate the built-in mechanism from a wider input issue. It is evidence for diagnosis, not a permanent reason to ignore a damaged or liquid-exposed laptop.
Follow the specific cleaning instructions
Apple publishes a compressed-air procedure for certain MacBook and MacBook Pro keyboards. Follow its model scope, angles and handling instructions instead of applying a generic forceful spray to every laptop.
Do not pry up keycaps or introduce liquid to loosen a key. If the device has been exposed to liquid, stop and seek hardware guidance rather than repeatedly testing it.
Know what a sound app can tell you
A sound indicates the app received an event through its input path. It cannot establish that the switch is mechanically healthy, that no presses were missed or that a text field interpreted the key correctly.
If the issue persists after appropriate checks, arrange service. For a setting-related delay, Slow Keys troubleshooting is a more relevant next step than changing sound themes.
Sources: Apple’s keyboard cleaning procedure, Slow Keys.