Read-Along
A Playhead for Generated Speech
Spoken output is bound word by word to the visible text, which makes the answer addressable in time: click a word to seek to it, drag a phrase to quote it, and stop the assistant anchored to a span rather than to a moment. Every other span pattern here — Citation Trail, AI Provenance, Bias Flag — annotates a static artifact the reader scans at their own pace; this is the only one with a clock. The binding itself is mature (Speechify, ElevenLabs Reader, Apple Books); the half that matters, interrupting at a phrase rather than at a timestamp, ships nowhere yet.
Framing
The problem
Spoken output is a stream you can only stop wholesale, so objecting to one sentence means killing the whole answer and starting the ask again.
The pattern
Bind the speech to the visible text word by word, so the answer becomes addressable in time — seek to a word, quote a phrase, and interrupt anchored to a span.
Why chat breaks here
A transcript has no clock: it can show what was said but not where the system is in saying it, so there is nothing to point at while it speaks.
Risks
Stopping at karaoke is the trap — word highlighting alone is a decade-old reading feature, and without seek, quote and span-anchored interrupt the binding buys nothing.
Avoid when
The answer is short enough to hear out; a playhead over two sentences is ceremony.
DOPE evaluation
- Directability
- Click any word to move the playhead there, or select a phrase and stop the assistant on that span — correction lands where the error is, not where the clock happened to be
- Observability
- The spoken word is the highlighted word, with its exact timestamp on screen, so what the system is saying and where it is are never inferred from audio alone
- Predictability
- Every word carries a start and end time before playback, so seeking is exact and the same span is addressable twice
- Explainability
- An interrupt reports the span it caught — the sentence, not the millisecond — so the assistant can say what it thinks you objected to
In the wild
- ElevenLabs Reader
- Speechify
- NotebookLM Audio Overview
FAQ
When should I avoid the Read-Along pattern?
The answer is short enough to hear out; a playhead over two sentences is ceremony.
What problem does Read-Along solve?
Spoken output is a stream you can only stop wholesale, so objecting to one sentence means killing the whole answer and starting the ask again.
Why is chat the wrong fit for this?
A transcript has no clock: it can show what was said but not where the system is in saying it, so there is nothing to point at while it speaks.