DAF Delayed Auditory Feedback app for iPhone and iPad

This app induces a curious psychological phenomenon in which your speech is severely jammed.

If headphones are not found on your device, the app alerts that headphones WITH a mic are necessary to experience the speech-jamming phenomenon.

Move the sound volume slider to the right SLOWLY while saying something. You will hear your own voice from the headphones. Set the sound volume to a comfortable level.

Set the delay level to about 150 ms using the delay slider, and say something. You will hear your voice with the delay. This procedure is called Delayed Auditory Feedback (DAF).

DAF is known to have an effect to interfere with your speech process. Try to say several tongue twisters. You will experience a veeeery hard time. This phoenomenon is called artificial stuttering.

If DAF is not so effective, try to adjust the delay level. The most effective delay is different among individuals (as is often the case with most psychological phenomena).

Tap the Replay button to confirm your utterance in the last few seconds. You can confirm how severely your speech was jammed.