Originally published February 2022. Updated May 2026 to reflect current tools and research.
A large-scale preregistered randomized controlled trial published in 2025 found that children using visual-acoustic biofeedback made progress 2.4 times faster than children receiving traditional therapy. That’s not a small effect. That’s the kind of result that can (and should) change how we practice.
So why aren’t more SLPs using biofeedback?
Cost and time. That’s almost always the answer.
Ultrasound biofeedback is incredible. I actually own an ultrasound unit and use it in my practice – the real-time visual of tongue movement is genuinely powerful, especially for kids who’ve been stuck for years. But ultrasounds cost thousands of dollars. Some SLPs pursue grants to fund them, and it’s worth exploring if you work in a research-friendly setting. For most SLPs? It’s just not realistic (yet).
Here’s the thing though: ultrasound isn’t the only option. Visual-acoustic biofeedback works differently – instead of showing tongue position, it shows the acoustic properties of the child’s speech as a real-time wave. The child adjusts what they’re doing with their mouth and can see immediately whether those adjustments are moving their sound closer to the target. It’s validated by rigorous clinical research, it runs on a laptop or tablet, and – importantly – some versions are completely free.
The staRt App: Free, Research-Backed, and Incredibly Useful
The best free option out there, in my opinion, is staRt, a visual-acoustic biofeedback tool developed at NYU by Dr. Tara McAllister and her team of researchers. I have been using this app since 2022 and it has completely changed the way I treat the R sound.Disclosure: I started recommending staRt publicly in 2022 – years before I ever met Dr. Tara McAllister, the researcher behind it. I found it on my own, started using it with my students, and wrote about it because it genuinely changed how I was treating the R sound. I now have a professional relationship with Dr. McAllister, but my opinion of this tool has never changed. It’s still my top recommendation.
Head to bitslabstart.com to access it directly in your browser. Here’s what it does: the child speaks into a microphone and sees their speech rendered as a wave in real time. The goal is to get the third formant peak to align with a target line – a visual cue that corresponds to accurate R production. When the peaks match up, the sound is right. When they don’t, the child can see exactly what direction to adjust. If you’ve never used it before, start here. This tutorial walks you through the basics:
And if you want to go deeper, the full quickstart playlist covers everything from setting your target to running a Word Quest session: staRt Quickstart Playlist →
A few practical notes for using staRt in sessions:
- Set your target frequency based on the child’s age and sex. The app has a built-in reference table for this under SLP Resources. Don’t skip this step – it matters for accuracy.
- Start with the tutorial mode before jumping into Word Quest, especially with younger kids. It helps them understand what they’re looking at.
- The wave can be sensitive to background noise. A quieter room and a decent microphone make a real difference.
There are other options for free biofeedback tools as well. We’ve discussed my personal favorite but others include:
Praat Software
Praat is a free acoustic analysis program from the University of Amsterdam. It looks like it was built in 1997 because it basically was, but don’t let that fool you – it’s a serious research tool that SLPs can use to analyze recordings and generate acoustic visualizations. I made a tutorial to make the learning curve less painful: watch it here. Just do your own research before downloading anything to a school or district device.
Rtgram
Rtgram is a Windows-only real-time spectrogram tool from University College London. I haven’t used it much personally because I’m not a Windows user, but it functions similarly to Praat and is worth knowing about if you’re on a PC.
Why This Matters Beyond the Clinic
Here’s something worth saying out loud: biofeedback isn’t just a tool for kids who are “almost there.” The research shows it’s particularly effective for children with persistent, treatment-resistant errors – the kids who’ve been on your caseload for years without meaningful progress. These are also the kids whose families are increasingly looking for home practice solutions that actually work.
Visual-acoustic biofeedback is one of the most promising bridges between what happens in a session and what a child can do on their own. That’s not just good for outcomes – it’s good for caseload management, for parent confidence, and ultimately for the child who doesn’t want to carry this sound into middle school or beyond.
Start with staRt. It’s free, it works, and your students will be genuinely fascinated by seeing their own speech in real time. That engagement alone is worth something.
Have questions about using biofeedback in your practice? Follow @RocktheRSpeech and @BitsLabstaRt on Instagram.
Keep rockin’ that R, friends!
