Learn About the Mumble Melody Study

Who We Are:

We are a group of researchers from MIT running a 1-month clinical trial exploring new auditory feedback approaches to help increase fluency for People Who Stutter (PWS). Our application Mumble Melody provides different modes that alter your voice in real time. The Mumble Melody app is a work-in-progress based on our research that aims to gather user feedback and better understand what aspects of the experience are most important for PWS. To be eligible for this study, you must:

  • Identify as a person who stutters
  • Have a compatible iPhone, iPad or Mac
  • Have a SEPARATE browser-supporting device with a microphone
  • Be 18-years-old or older
  • Live in the United States.

If you are eligible and are interested in participating, please fill out this form: redcap.link/mumblemelodystudy.


Stuttering affects 1% of adults and 8% of children, and there are 70 million PWS worldwide. Stuttering-like-disfluencies include blocks, repetitions, and prolongations. While there is no cure for stuttering, the Mumble Melody team is investigating audio-based approaches that may help increase fluency for people who stutter. Previous research has looked at the effects of simple vocal transformations - particularly pitch/frequency shifts and delays - but none have altered the acoustic landscapes using digital technologies that enable more complexity and nuance. The long-term benefits from altered auditory feedback from pitch and frequency shifts are limited by a relatively unpleasant listening and speaking experience. Our data shows our novel modes to have extended benefits compared with pitch shifts and delays in terms of effects, pleasantness, and control.

About This Study:

The purpose of this study is to use altered auditory vocal feedback to increase fluency in people who stutter and to examine changes in this effect over the course of a one month period occurring outside the laboratory setting. It will have 3 components: (1) daily sessions on your mobile device using an iOS app (time flexible) (2) a 10-15 minute survey at the beginning of the study and a 10-15 minute survey at the end of the study (3) A 15 minute eligibility screening session, one 40 minute baseline session at the beginning of week 1, and four 30min testing sessions at the end of each week, on your computer using a web platform for a period of 4 weeks. We won’t be collecting any personal data or voice data. Here is a link to download this app.


The approach provided in our study does not intend to cure or fix stuttering. Stuttering is a very complex condition, still not completely understood by the research community, and it comes with influential social and identity-forging elements. Our goal through distributing this app is to gather feedback from potential users to help improve the science and research on stuttering. Please be aware that the research is ongoing, and Musically Modulated Auditory Feedback might not work for all users. The Mumble Melody application will automatically deactivate in about a month.

Will It Work On My Device?

Mumble Melody is compatible with the:

  • iPhone, iOS 12.0 or later
  • iPad, iPadOS 12.0 or later
  • Mac, macOS 11.0 or later, with Apple M1 chip or later
  • iPod touch, iOS 12.0 or later

Contact Us: If you have any questions or concerns, do not hesitate to contact us at mumblemelody@mit.edu

Stuttering Study Mailing List: We are regularly launching new studies to support research on stuttering. If you are interested in being contacted to participate in such studies please fill out this form.

Learn More About Our Reseach: Click here to learn more.