TL;DR. StutterFlow is a stuttering app for focused DAF practice. Wear wired earbuds, pick a delay (50/100/150/200 ms), and practise for 5–15 minutes. Audio runs through Apple's AVAudioEngine on device; nothing is recorded or uploaded.
What it is
StutterFlow is a delayed auditory feedback (DAF) practice tool. You speak; the app plays your voice back through your headphones with a small delay. For most adults who stutter, this immediately slows speech and reduces stuttering — see how DAF works and the science.
The app is built around the daily practice loop:
- Pick a delay. Light (50 ms), Golden (100 ms), Therapy (150 ms), Heavy (200 ms).
- Put in wired earbuds.
- Practise for 5–15 minutes — read aloud, drill word lists, run a sound-specific routine, or use it during a real call.
- Take the headphones off and try the same thing without DAF. That's the transfer block.
That's the whole loop. We didn't try to build a full clinical platform. We built one tool, well.
Who it's for
- Adults who stutter and want a daily practice tool that fits a commute or a coffee break.
- People between or alongside SLP sessions who need structure for the homework part of therapy.
- Speech-language pathologists who want a clean DAF tool to recommend to clients without the hardware-device price tag.
- Older teens with their family's and clinician's involvement.
It is not for very young children — see stuttering in children for what's appropriate at preschool and school age.
What's in the app
- Four DAF delay presets: Light (50 ms), Golden (100 ms), Therapy (150 ms), Heavy (200 ms). Most adults find their sweet spot in 75–150 ms.
- Real-time audio through AVAudioEngine. Apple's native low-latency audio engine, so with wired headphones the delay you set is the delay you get.
- Sound library. Word and phrase drills organised by initial sound — useful for working on personal trigger sounds.
- Daily routines. 5-, 10- and 15-minute structured sessions combining breathing, voice warm-up, drills and reading.
- Transfer mode. Short DAF-on / DAF-off cycles inside a single session to build carryover.
- No account, no upload, no recording. See privacy below.
Privacy
StutterFlow processes audio entirely on your device. The microphone signal goes into AVAudioEngine, the delay is applied, the output goes to your headphones. Nothing is recorded; nothing leaves the device. There is no account to create.
The only data that ever crosses the network is an App Store purchase receipt if you upgrade to a pro tier. We don't collect analytics that fingerprint your speech. We don't sell anything to anyone.
This isn't a marketing position — it's a structural choice. Audio belongs to you.
How to set it up
- Get wired earbuds. Any pair will do. Bluetooth headphones are not recommended for DAF — wireless latency is variable and unreliable.
- Install StutterFlow from the App Store.
- Microphone permission — required for the app to do anything. Grant it.
- Pick Golden (100 ms). The most common starting delay; adjust later based on what feels right.
- Read a paragraph aloud for 3 minutes. Notice the slowed pace and softer onsets.
- Take the headphones off and read the same paragraph. This transfer block is where carryover happens.
Aim for five sessions a week. After 4–6 weeks many users notice changes — first in DAF-supported speech, and sometimes increasingly in unsupported speech — but response varies, and progress is easier to judge with recordings or clinician feedback.
How it pairs with therapy
StutterFlow is designed to complement, not replace, work with a speech-language pathologist:
- An SLP teaches you the right techniques (prolongation, easy onset, light contact) and gives feedback.
- StutterFlow gives you the daily 5–15 minutes of practice that consolidates those techniques.
- Together they cover both halves of a stuttering-management plan: what to do, and the repetition that makes it stick.
If you don't have an SLP yet, stuttering treatment and how to find an SLP cover what to look for.
What StutterFlow is not
- Not a cure. No app, device or program cures stuttering. See is stuttering curable?.
- Not medical advice. It's a practice tool, classed by Apple as Health & Fitness, not Medical. A persistent disclaimer banner in the app and on this site makes that clear.
- Not a clinical assessment. For severity assessment, prognosis or therapy planning, see a qualified SLP.
- Not a hardware replacement for users who genuinely need all-day DAF. Some adults benefit from in-ear hardware DAF devices for whole-day wear in jobs that demand constant speaking. StutterFlow is for daily practice sessions, not all-day wear.
Pricing
The core practice loop is free. An optional pro tier unlocks extended sound libraries, multi-week structured programs and additional drill content. The pricing is intentionally lower than hardware DAF devices and most subscription-based clinical apps. We'd rather have the app in the hands of a million people who stutter than charge a few of them premium prices.
Get the app
StutterFlow is available on the App Store.
If you have questions, the DAF page explains the technology, exercises covers the daily-practice side, and the editorial policy covers how this site is built and reviewed.
