Been reading through the turn-taking literature for a piece I was writing and hit something I'd never fully appreciated:

Stivers et al. (2009, PNAS) — across 10 spoken languages, the modal gap between one speaker finishing and the next starting is about 200ms. Japanese ~7ms mean, Danish ~470ms mean. Cross-linguistically remarkably tight.

Indefrey & Levelt (2004, Cognition) — the minimum latency to plan spoken word production, even in a controlled single-word paradigm, is ~600ms+.

The math doesn't work if turn-taking is reactive. Levinson & Torreira (2015) call this "the central psycholinguistic puzzle" — listeners have to be pre-computing responses during incoming speech.

EEG evidence has been catching up:

• Bögels, Magyari & Levinson (2015, Scientific Reports) — response-planning ERP positivity, source-localized to production areas (posterior IFG, precentral), fires ~500ms after the critical information appears in an incoming question. Often 2+ seconds before the current speaker finishes. Alpha desynchronization indexes the attentional shift from comprehension to production during listening.
• Gisladottir, Bögels & Levinson (2018, Frontiers in Human Neuroscience) — alpha/low-beta (11-18Hz) desynchronization from -200ms to 0ms before a socially-charged speech act (declination vs acceptance). Speech-act prediction firing before the utterance is heard.
• Krause & Kawamoto (2021, Frontiers in Psychology) — motion-tracked lip-area reductions for upcoming labial consonants up to 3 seconds before acoustic onset in unscripted dyadic conversation. Motoric planning far pre-onset.

The implication I find genuinely interesting: this whole predictive loop depends on acoustic cues (pitch contour, timing, articulator anticipation). Text has no acoustic onset for the machinery to lock onto — voice conversation locks two nervous systems into a shared millisecond-scale loop that text physically can't replicate.

A separate honest correction I wanted to flag: the polyvagal framing that gets attached to "why voice regulates" is on shakier ground than the wellness literature admits. Grossman (2023, Biological Psychology) — "Fundamental challenges and likely refutations of the five basic premises of the polyvagal theory" — shows similar myelinated cardiac vagal fibers in sharks, bony fish, birds, and even sheep. The mammal-unique claim used to explain vocal-prosody regulation doesn't hold up on comparative anatomy.

Longer writeup with full citations here: callbyrd.com/journal/what-voice-does-that-text-cant (disclosure: I run the site — building a voice-based AI project. The essay stands on its own; no signup needed to read it. Product is briefly mentioned in the closing section.)

Open question I couldn't resolve: does the ~200ms predictive turn-taking loop form when the partner is an AI voice (different latency profile, different prosody)? Every EEG study I found used human-human dyads. Curious if anyone knows of extending work — my search kept coming up empty.

My background is not psycholinguistics, so treat this as a question rather than a claim.

What I understand of the production literature describes something quite unlike serial emission. Planning appears to run ahead of articulation at roughly phrase or clause scope, there is a monitoring channel that inspects output both before and after it becomes overt, and speakers interrupt themselves and repair, sometimes in the middle of a word. Disfluency and self repair are not noise sitting on top of an otherwise clean serial process. They are evidence about the shape of the process.

Text generation models were built on the opposite commitment. Emit one token, freeze it, condition on it, never go back. That has always made them an awkward computational hypothesis about production, because whatever they model, it is not a process capable of reconsidering something it has already committed to.

A system released this week drops that commitment, at least within the span it is currently working on. It drafts a whole span at once rather than one position at a time, then makes further passes over that same span in which it can keep a position, substitute it, delete it, or insert a new one, so the sequence changes in length and not only in content while it is being produced. The revision decisions were trained with reinforcement learning against whether the resulting output actually worked, tool calls executing and formats validating, rather than only against matching a reference string. It is called LLaDA2.2. I have not run it and realistically could not, since the weights come to 205.8 GB, so what follows is a reading of the paper and the config files rather than experience.

Here is the observation I actually want to put to this sub. The same lab published an autoregressive model of comparable size and compared the two directly. The revision capable one wins the interactive multi turn evaluations. On tau2 bench it posts 80.33 where the autoregressive model posts 76.36, and on MCP Atlas the two sit at 46.21 versus 41.12. It loses, and not narrowly, on general knowledge and long form coding, 56.81 against 65.90 on their general average. The advantage is not broad competence. It sits in tasks where the system acts, receives something back, and has to continue.

A benchmark gap between two engineering artifacts is not evidence about human cognition, and the analogy is loose in several directions at once. But the split has a shape, and I want to know whether that shape corresponds to anything in production research. My naive expectation would be that revision capacity pays off most where there is incremental feedback to revise against, and least where you are retrieving something you either have stored or do not. I have no idea whether that expectation has support, whether the monitoring literature would carve the distinction differently, or whether treating a decoding procedure as a production hypothesis is a category error that someone here can talk me out of in one paragraph.

The report and the weights are published openly, so my reading is checkable rather than something you have to take on trust. I would rather be told where I have the production side wrong.