l10n: String Length and Verbosity across Languages

A few months ago I was discussing with @kaze about the truncation plague on Firefox OS, and he came out with a sentence that left me doubtful:

according to the desktop metrics I had, French is the least compact locale and Chinese is the most compact one

So I had to check it somehow 😉 (in Italy they would call me Saint Thomas for being skeptical).

The basic idea was simple: use Silme to analyze all locales available in Mozilla l10n repositories, comparing string lengths between English and another language.

Here’s the resulting Python script (beware my slowly improving programming skills) and a table with the results (data can be sorted by clicking on column headers).

Sample and Reference

I’m using mozilla-beta as a reference, and comparing each locale against en-GB. Why not en-US? The reason is simple: en-US strings are scattered across the entire mozilla-central repository, so I should do tricks like Transvision in order to create a pseudo en-US string-only repository. Using en-GB leads to less precise results (see below), but for the sake of this analysis I considered it an acceptable compromise.

I’m not checking all folders, only the main ones (‘browser’, ‘dom’, ‘mail’, ‘mobile’, ‘netwerk’, ‘security’, ‘services’, ‘suite’, ‘toolkit’, ‘webapprt’). This still generates an archive of almost 18,000 strings for locales translating all products, so it seems a decent sample.

Caveats and Weird Results

String 1: en-GB 2 characters, locale X 4 characters -> +2 characters, +100%
String 2: en-GB 8 characters, locale X 4 characters -> -4 characters, -50%
Average for locale X: -1 characters, +25% (sum of differences divided by total number of items).

Not sure if this is the best choice, but I couldn’t think of an alternative. Note also that I’m ignoring single character strings (access keys, shortcuts).

In the table you’ll see a global column (average results) and “buckets”, with string groups based on en-GB original length. Too bad these groups are often unreliable because of the “concatenation conundrum”, where one string could be created by concatenating 3 different labels.

Typical example to create a sentence with a link (note that concatenation should be always avoided):

sentence.before = Hey, this is a
sentence.link = very interesting link
sentence.after = .

In Italian this could be localized as

sentence.before = Ehi, questo
sentence.link = link
sentence.after = è veramente interessante.

Do you see what just happened here? Length comparison based on groups just became less interesting, both averages and maximum/minimum differences.

Anyhow, here’s a good image (graph based on global difference in percentage) that I’d like to call “Why using English as a reference for designing UI may not be a great idea”.

Length Comparison - mozilla-beta
Open link in a new tab/window to see the full image

Why not use Gaia directly?

This sounds like a good idea: we have a real en-US repository, and we don’t have concatenations. But there are some disadvantages as well:

  • Most locales already did at least two rounds of QA, so a lot of strings have already been (heavily) shortened to fit in the UI. So data could be less useful and interesting.
  • Several locales are incomplete on gaia-l10n. For this very reason I excluded all locales with less than 1000 strings translated.

Here’s the same table for Gaia. And, again, a similar graph based on global difference in percentage.

Length Comparison - GaiaOpen link in a new tab/window to see the full image

Fun facts:

  • We know that en-GB is 0.16% longer than en-US, at least on Gaia.
  • A simple word as “OK” (2 characters) can become as long as “Kulungile” (9) in Xhosa, or “Ceart ma-thà” (12) in Scottish Gaelic.



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6 responses to “l10n: String Length and Verbosity across Languages”

  1. […] La storia completa è disponibile sul blog in pseudo inglese. […]

  2. Neil Rashbrook Avatar

    Now you just need a table of typical font widths so you can compare display lengths!

    I found that table’s sorting unintuitive; it always reverses the direction by which the column was previously sorted, even if the column wasn’t the previously sorted column. By comparison I’m used to tables that either always sort ascending when you change column or remember the sort direction of the previously sorted column, and I can even imagine a use case for remembering the sort direction by which the column was itself previously sorted without reversing it if the column wasn’t the previously sorted column.

    Also while I’m here I’d like to claim that “OK” is an abbreviation rather than a word.

  3. flod Avatar

    Sorting is made with a jQuery plugin, and I agree it’s a bit awkward when you move back to a column previously sorted.

    Also while I’m here I’d like to claim that “OK” is an abbreviation rather than a word.

    Right. Ironic enough, I checked the origin of OK yesterday because of a movie.

  4. glandium Avatar

    You really want to check rendered sizes instead of string lenghts because a character is not the same length in different scripts. You can typically write several latin characters in the horizontal space taken by a chinese, korean or japanese character. Also, some scripts combine characters in some way.

  5. Robert O'Callahan Avatar
    Robert O’Callahan

    I think it might make a significant difference to compare rendered text widths rather than just string length. A lot of languages use combining marks which count as 1 character each but don’t add to the rendered text width.

  6. flod Avatar

    I’m aware that would be a more useful metric, not sure how hard it would be to calculate though.
    Also: when reading a string I have no idea of its role, and role on Gaia means different font size.

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