“Expansion rate.” Like the titular creature of the 1958 movie The Blob, it can be a horrific monster.

Anyone who has had to design web or mobile UI/UX for various international audiences has run into it. So has anyone who has made different language versions of the same web banner ad or multi-page brochure or book layout. Our own CEO, Michel Lopez, has written in the past on the subject. His observations bear revisiting.

Expansion Rate, Defined

When you go from one language to another, and you end up with more characters, even more words, that is the expansion rate for translation. Across the industry, it is usually defined by the percentage of additional words needed to describe something from one language in a different language. For example, when translating from (US) English-to-French, you will typically find that the text “expands” by about 15% – 20%.

Conversely, when you would go from French-to-English, you would see a contraction rate of 13% – 17%. That is usually less of an issue, but still may set visual or editorial professionals needing to deal with truncated translated content twitching.

To give a hat-tip to our industry colleagues over at Kwintessential in the UK, they have a rather handy table of what you can expect for expansion or contraction rates between twenty languages (and regional variations).

Character Expansion

It is not just word-based expansion that authors and designers need to worry about. As the W3C notes, in their document for translation expansion for the web, Chinese and Korean characters often require about twice the visual space (width) per character as Latin-alphabet languages.

Look at the very title of this article: “Taux de Foisonnement – Expansion Rate.” In English, it is “Expansion Rate” (14 characters total, including one space). But in French we have «Taux de Foisonnement» (20 characters, including two spaces). That’s an expansion rate (and converse contraction rate) of +43% (–30%).

It Even Happens in Same-Language Localization

Even localizing text from US English to UK English will see some expansion, often in terms of character-count. For example, the typical alteration of “armor” to “armour” and “color” to “colour.” But there are exceptions. While American “soccer” (6 characters) is shorter than British “football” (8 characters), the American English word “elevator” (8 characters) is twice as long as the British “lift.”

It can cut both ways, idiomatically. The abbreviated American vernacular “gas” is half-as-long as the British “petrol,” but the full word “gasoline” is longer. Which you use may depend on the context of the content, such as whether its use is conversational or technical.

How a Translator Can Help

Don’t just shrink the font size to cram everything into the space available!

When visual real-estate and reader comprehension matters, high-quality human translators and editors can make sophisticated and subtle decisions on how to fit translated content for space. Their toolkit is their linguistic expertise: making idiomatic language and phrase substitutions, removing excessive or repetitive verbiage, using simpler (but still precise) words to convey the same meaning, rewording passages entirely (if need be), and any other necessary modifications.

For these issue aren’t solved by the science, but by the art of translation.

Have you ever run into issues of expansion or contraction in your own translation projects? Have you ever had a project expand like The Blob past the boundaries of your dialogue boxes and page counts? How did it affect the quality of the end products? If you have had past experience, or a current translation project requiring the keen eyes of our linguists, let us know! Email us at [email protected].