Sung lines and read copy are not dialogue
Dialogue is one register among several. A sung line has fixed timing imposed from outside, and read copy has a rhythm that belongs to the medium rather than to a character. Both behave differently from a conversation. As of 2026-09-12.
| Register | What sets the timing | What breaks first |
|---|---|---|
| Dialogue | The shot length, and the writing | Pacing, on long lines |
| Read copy | A slot, usually to the second | Emphasis, which lands generically |
| A sung line | A bar, imposed from outside | Pitch and sustain, not the words |
Inclusion rule. Registers of spoken delivery a production might ask for, compared by what constrains each. Order. Fixed order: dialogue first, then the two registers it gets confused with.
1External timing is a different constraint from a shot ceiling
A line of dialogue has to fit a shot; a sung line has to fit a bar, and the bar was decided by music that already exists. That inverts the usual order, because the audio is the fixed element and everything else is fitted to it.
One entry in this register documents a route for exactly that: audio-to-video, where an existing track drives the generation. It is the only published arrangement here that suits a musical number.
2Read copy fails in a way dialogue does not
Advertising copy is written to be emphasised, and emphasis is the property a synthesised read handles worst. A line can be perfectly intelligible, perfectly timed and completely flat, which is fine for an explainer and fatal for a sell line.
Nothing in this register offers a lever for it. Rewriting the copy so the emphasis falls on sentence structure rather than on delivery is the only approach available.
3Naming a register is unusual and worth noticing
Only one vendor here names anything other than speech. Doing so says the endpoint was built with more than one use in mind, which is more informative than a language claim with no names attached to it.
It is also in the wrong column for a market decision. A producer asking whether a series can ship in German gets nothing from it; a producer asking whether a musical number is in scope gets an answer nobody else provides.
4Where the published detail is logged
What is described above is how the techniques work in general. Which models document which of them, in whose words, is kept in the speech controls table with a date on every field.
- A second control — four levers documented once each
- The language column — where the register claim also sits
A mechanism note rather than a documented field. Nothing here is attributed to a model, and nothing here is a claim about one. The sourced material is on the speech controls table. Related: First tests, Subtitles and length.