Fluency Lab
Delayed auditory feedback, a pacing metronome and paced reading, all in one page. Free, unlimited, and nothing you say is recorded or uploaded.
Free without limits, and private. There are no credits and no daily cap. Audio is processed live inside your browser, never saved, and never sent anywhere.
Not medical advice. Fluency Lab is a self-guided practice aid, not speech therapy, diagnosis or treatment. It does not replace a speech and language pathologist. If stuttering is affecting your daily life, please speak to a qualified clinician.
1. Delayed auditory feedback
Your own voice is played back to you a fraction of a second late, which many people who stutter find slows and steadies their speech.
Headphones required. Without headphones the delayed sound reaches the microphone again and creates a loud feedback howl. Put headphones on and keep the volume moderate before you start.
Microphone off.
Before you start: are you wearing headphones or earphones? Speakers will cause a feedback loop that is unpleasant and loud. Start at a low volume and raise it slowly.
2. Pacing metronome
A steady beat to speak along with. Slower beats give you more room on each syllable.
3. Paced reading
Read out loud, one highlighted group of words per beat. Paste your own text or load a practice passage.
Your text will appear here as highlighted word groups once you type or load a passage.
How to use Fluency Lab
- Put headphones on. This matters for the delayed feedback section, because speakers send the delayed sound straight back into the microphone and create a loud howl.
- Set the delay slider, start around 75 ms, then press "Start feedback" and allow microphone access when your browser asks. Speak normally and listen to your voice coming back slightly late.
- Try the pacing metronome on its own. Set a slow tempo, around 50 to 70 beats per minute, and speak one syllable or one word per beat until it feels comfortable.
- Load a practice passage or paste your own text, choose how many words fall on each beat, then press "Start reading" and read the highlighted group out loud as it moves.
- Watch the practice timer at the top. Short, regular sessions tend to help more than one long session, and the timer resets automatically each day.
Why use ZillaKit's Fluency Lab?
Delayed auditory feedback devices have been used in stuttering practice for decades, and dedicated units can be expensive. This page does the same core job with the audio engine already built into your browser: it takes your microphone, delays it by an amount you choose between 20 and 250 milliseconds, and plays it back into your headphones in real time. There is nothing to install, nothing to buy, and no account to create.
The three sections work together or separately. Delayed feedback changes how you hear yourself, which for many speakers naturally slows the rate and reduces blocks. The metronome gives you an external rhythm to hang syllables on, a technique often called rhythmic or paced speech. Paced reading joins the two ideas: your text is broken into small chunks and highlighted one chunk per beat, so you always know exactly how much to say before the next beat arrives. You can slow the pace right down to one word every two beats when a passage is difficult, then speed it up as it becomes easier.
Privacy is built into how the tool works rather than promised in a policy. Your microphone stream is connected to a delay node and an audio analyser inside the page, then sent straight to your headphones. Nothing is recorded, nothing is buffered to a file, and no audio ever leaves your device. The only thing stored is a small count of minutes practised today plus your slider settings, kept in your own browser. Because fluency practice is a daily habit rather than an occasional download, the page is completely free with no limits, no credits and no sign up, and it works in both light and dark themes on phones, tablets and computers.
FAQ
What is delayed auditory feedback?
Delayed auditory feedback, or DAF, plays your own voice back to you a short time after you speak, usually between 20 and 250 milliseconds. Hearing yourself slightly late tends to slow speech down and, for many people who stutter, makes speaking feel easier. It is a long established practice technique rather than a cure.
Why do I really need headphones?
Because the delayed sound is played out loud, speakers feed it back into your microphone, which delays it again and quickly builds into a loud howling loop. Headphones or earphones keep the output away from the microphone. Start with the volume low and raise it gradually.
Is my voice recorded, saved or uploaded?
No. The microphone stream is connected directly to a delay and an analyser inside the page and sent to your headphones. Nothing is written to a file, nothing is stored and no audio is transmitted anywhere. Closing the tab ends the stream entirely.
What delay should I choose?
75 ms is a common starting point. Shorter delays around 20 to 50 ms feel subtle, while longer delays of 150 ms and above force a much slower rate and can feel strange at first. Try a few settings and keep the one that makes speaking feel easiest for you.
Does this replace speech therapy?
No. Fluency Lab is a practice aid you can use between sessions or on your own, not therapy, diagnosis or treatment. A speech and language pathologist can assess your speech properly and build a plan around it. Use this tool alongside professional support, not instead of it.
The microphone will not start, what should I check?
Check that you allowed microphone access when the browser asked, and that no other application is holding the microphone. The page also needs a secure https connection for microphone access to be offered at all. If you blocked access earlier, reset the microphone permission for this site in your browser settings and reload.
Is Fluency Lab free?
Yes, completely, with no usage limits, no credits and no account. Practice tools for speech should be available whenever you need them.