How Do Subtitles and Dubbing Work? Two Ways of Losing Something Different

Subtitling is constrained by reading speed far more than by translation difficulty, and the professional standards are specific:

• •A maximum of two lines on screen at once, since a third pushes the eye too far from the image
• •A limit of roughly thirty-seven to forty-two characters per line depending on the language and platform
• •A reading speed limit, conventionally around seventeen characters per second for adults and lower for children, which is what actually determines how much text can appear
• •Minimum and maximum durations, since a subtitle flashing for under a second cannot be read and one lingering after the line has ended reads as an error
• •Respecting shot changes, since a subtitle spanning a cut causes the viewer to re-read it
• •Line breaks placed at syntactic boundaries so each line is a readable unit
• •The practical result is that subtitles routinely condense dialogue by a substantial proportion, which is why viewers who understand some of the source language notice material missing, and the omissions are usually redundancy rather than content

Dubbing replaces the dialogue track with a new performance and is limited by the picture rather than by the viewer. Lip synchronisation operates at three levels: phonetic synchrony, matching the visible mouth shapes particularly for open vowels and closed consonants at the start and end of lines; isochrony, matching the duration so the replacement starts and stops when the mouth does; and kinetic synchrony, matching gestures and body movement. Meeting those simultaneously in another language with different word lengths and word order is extremely constrained, and a dubbing translator writes something that fits rather than translating directly, which is a distinct craft called adaptation. Voice casting carries its own weight, since audiences in dubbing countries associate particular voice actors with particular stars across decades and notice a change. The dubbing must also be mixed into the music and effects track supplied by the producer, which is why that separate track exists at all.

The division into subtitling and dubbing territories is largely historical and economic rather than a matter of taste. Dubbing became standard in countries with large domestic markets that could absorb the cost, principally Germany, Italy, France and Spain, and in several of those the practice was established under governments in the 1930s that had political reasons to control what foreign films said, which is a documented factor in Italy and Spain. Subtitling became standard in smaller markets where dubbing every import was uneconomic, including the Nordic countries, the Netherlands and Portugal, and those populations show consistently higher foreign language proficiency, with researchers arguing that decades of exposure to subtitled English is a genuine contributor rather than a coincidence. A third approach, voiceover narration with the original audible beneath, is common in Poland and parts of Eastern Europe and is cheaper than dubbing. Streaming has blurred these lines by offering both for everything, and viewing data suggests a substantial shift towards subtitled viewing among younger audiences even in dubbing countries.

Subtitling preserves the original performance entirely, including tone, accent, timing and the actor's voice, and costs the viewer attention, since reading occupies the eyes that would otherwise be watching, with eye-tracking research confirming that subtitle readers spend a substantial proportion of the time looking at text rather than image. It also condenses, losing nuance and much of the texture of informal speech, and cannot easily convey overlapping dialogue. Dubbing preserves the viewer's attention on the image and loses the original performance, replaces vocal characterisation with someone else's, and introduces its own artificiality when synchrony is imperfect. It also enables invisible alteration, since a dubbed line can say something the original did not with no way for the audience to detect it, which is why the political history matters. Both face the same intractable problems with humour, wordplay, songs, cultural references and dialect, which are where translation is genuinely impossible rather than merely constrained and where the translator must choose what to sacrifice.

Subtitles are limited by reading speed rather than by translation, typically two lines of around forty characters at about seventeen characters per second, which forces substantial condensation. Dubbing is limited by the picture, matching mouth shapes, line duration and gesture, so the translator writes something that fits rather than translating. Dubbing territories were established in large markets, sometimes under governments with reasons to control content, while subtitling countries show higher foreign language proficiency.