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Essentials: The Science of Learning & Speaking Languages | Dr. Eddie Chang

In this Huberman Lab Essentials episode, my guest is Dr. Eddie Chang, MD, a neurosurgeon and Chair of the Department of Neurological Surgery at the University of California, San Francisco (UCSF). We discuss the neural circuits underlying speech and language, including how the brain controls the larynx, vocal folds and articulators to shape breath into words. We also explore his pioneering work on speech neural prosthetics — brain-machine interfaces that allow paralyzed patients to communicate by decoding neural activity into speech and avatar-driven facial expressions. Additionally, we examine the neurobiology of stuttering, the role of auditory feedback in fluent speech, and the broader ethical questions surrounding brain augmentation technologies. Show notes: https://go.hubermanlab.com/b0qQsyP Watch more Huberman Lab Essentials: https://youtube.com/playlist?list=PLPNW_gerXa4OGNy1yE-W9IX-tPu-tJa7S&si=a1_sA7rUT-fE0OM5 Follow Huberman Lab Instagram: https://www.instagram.com/hubermanlab Threads: https://www.threads.net/@hubermanlab X: https://x.com/hubermanlab Facebook: https://www.facebook.com/hubermanlab TikTok: https://www.tiktok.com/@hubermanlab LinkedIn: https://www.linkedin.com/in/andrew-huberman Website: https://www.hubermanlab.com Newsletter: https://www.hubermanlab.com/newsletter Dr. Eddie Chang Lab: https://changlab.ucsf.edu UCSF academic profile: https://profiles.ucsf.edu/edward.chang UCSF clinical profile: https://www.ucsfhealth.org/providers/dr-edward-chang LinkedIn: https://www.linkedin.com/in/edward-chang-384746132 Timestamps 00:00:00 Speech & Language 00:00:23 Speech vs Language, Pragmatics, Semantics & Syntax 00:03:11 Larynx, Vocal Folds & Shaping the Breath 00:05:35 Crying & Laughter, Vocalizations vs Speech 00:06:37 Paralysis, Brainstem Stroke, ALS & Locked-In Syndrome 00:09:14 BRAVO Trial, Pancho & First Patient 00:11:07 Brain Surgery, Electrode Array & Decoding Speech 00:12:53 AI, 50-Word Vocabulary & Autocorrect 00:14:27 Neuralink, Brain-Machine Interfaces & Augmentation Ethics 00:19:23 Avatars, Facial Expressions & Non-Verbal Communication 00:22:50 Stuttering, Anxiety & Speech vs Language 00:26:02 Tool: Stuttering Therapy & Auditory Feedback 00:27:34 Recap & Acknowledgments #hubermanlab #health #science Disclaimer & Disclosures: https://www.hubermanlab.com/disclaimer

Andrew HubermanhostDr. Eddie Changguest
May 21, 202628mWatch on YouTube ↗

At a glance

WHAT IT’S REALLY ABOUT

How brain circuits create speech, and restore it with BCIs

  1. Speech is the motor act of shaping breath into sound, while language includes broader processes like meaning (semantics), intent (pragmatics), and grammar (syntax) across multiple modalities (speech, sign, reading).
  2. The larynx generates voiced sound via vibrating vocal folds during exhalation, and structures above it (pharynx, mouth, tongue, lips, jaw) shape that sound into intelligible consonants and vowels.
  3. Nonverbal vocalizations like crying and laughter can remain intact after injury to speech/language areas, implying partially distinct neural circuits for vocalization versus articulated speech.
  4. In the BRAVO clinical trial, implanted cortical electrodes plus machine-learning decoding enabled a long-paralyzed locked-in patient (“Pancho”) to produce words/sentences from neural activity using a constrained vocabulary and language-model autocorrect.
  5. The field is moving from research toward commercial neurotechnology, raising near-term ethical questions about invasive “augmentation,” access, and how richer communication (avatars, facial expressions) may change digital interaction and disability inclusion.

IDEAS WORTH REMEMBERING

5 ideas

Speech is a high-precision motor behavior layered on breathing.

Chang frames speaking as “shaping the breath”: exhale, generate voicing at the larynx, then sculpt that sound via coordinated movements of tongue, lips, jaw, and oral cavity—arguably among the most complex motor skills humans perform.

Language is broader than speech and spans multiple representational levels.

Beyond producing sounds, language includes extracting intent (pragmatics), meaning (semantics), and grammar/structure (syntax), and it can be expressed through modalities like sign language and reading—not just spoken words.

Crying/laughter can be neurologically separable from speech.

People with injuries affecting speech/language regions may still vocalize (moan, cry, laugh), suggesting older or distinct brain circuits can generate emotional vocal output even when articulated speech is impaired.

Locked-in syndrome is often a communication bottleneck, not a cognition deficit.

In brainstem stroke or advanced ALS, cognition may remain intact while pathways to the face/vocal tract and limbs fail, creating profound social isolation because thoughts cannot be expressed through normal motor channels.

Practical BCI speech restoration is a system, not a single decoder.

The BRAVO approach combines implanted electrodes, ML/AI pattern recognition, and language-technology tricks like context-based autocorrect to improve usability when neural decoding is imperfect.

WORDS WORTH SAVING

5 quotes

Some people would say it's the most complex motor thing that we do as a species is, is just speaking.

— Dr. Eddie Chang

If you have a stroke there, you could be thinking all the wild, creative, intelligent thoughts you have in the mind and the cerebrum, but you can't get them out into words or you can't get them out to your hand to write them down.

— Dr. Eddie Chang

This condition of what we call being locked in refers to this idea that you can have completely intact cognition and awareness, but have no way to express that, no voluntary movement, no ability to speak, and that is devastating because, uh, psychologically and socially, you know, you're completely isolated.

— Dr. Eddie Chang

I personally don't think that we've thought enough actually about what these kind of scenarios are gonna look like, and I don't think we've thought through all the ethical implications of what this means for augmentation in particular.

— Dr. Eddie Chang

Stuttering is a problem of speech, right? So the ideas, the meanings, the grammar, it's all there in people's stutter, but they can't get the words out fluently.

— Dr. Eddie Chang

Speech vs. language (pragmatics, semantics, syntax)Larynx/vocal folds and breath shapingVocalizations (crying/laughter) vs articulated speech circuitsLocked-in syndrome, brainstem stroke, ALSBRAVO trial and cortical electrode arraysAI decoding, limited vocabulary, language-model autocorrectAugmentation ethics, avatars, nonverbal communicationStuttering as a speech (not language) disorderAuditory feedback and stuttering therapy approaches

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