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In order to improve usability for non-English speaking users, the goal is to have OpenSesame adapt to the default language of the operating system. Very little technical skill is needed to contribute a translation.

If you want to provide a translation, it's recommended to first send an inquiry to or post a message on the forum, to make sure that your language is not already being worked on.

Starting OpenSesame with a specific language

By default, OpenSesame will try to use the default locale of your operating system, and fall back to English if a translation is not available. To start OpenSesame with a specific language, you can use the --locale command line argument. For example, to use the Italian translation start OpenSesame as follows:

opensesame --locale it_IT

This will look for a file called resources/locale/it_IT.qm, and fall back to English if no such file exists.

The five-step translation process

Step 1: Download translatables.ts

translatables.ts is an XML file that contains all the strings that are to be translated. You can download it from here:

At the top-right of the file, you will see a 'Raw' link. Right-click on this link and select 'Save file as' (or something along those lines, depending on your browser) to save the file your disk.

Step 2: Install QtLinguist

QtLinguist is a graphical tool that will assist you in the translation process. It's very user friendly, and allows you to simply select a string of (English) text and enter a translation.

Windows and Mac OS

You can download it as part of the Qt development toolkit ( or as a standalone program ( The standalone option is probably easiest for most people.


On Linux, the QtLinguist is generally available in the repositories. For example, on Ubuntu it can be installed with:

sudo apt-get install qt4-linguist-tools

Step 3: Open translatables.ts in QtLinguist

Now start QtLinguist and open translatables.ts. You will first be asked to enter a source and target language. Leave the source as it is: 'POSIX/ Any country'. The target language should be set to the language that you will translate OpenSesame into. Leave the Country/Region option at 'Any country'. You can change these settings later via Menu -> Edit -> Translation file settings.

Now you can start translating! On the left you will see a list of 'contexts'. These correspond to different parts of the OpenSesame GUI. The 'script' context corresponds to the translatable text messages that are generated on-the-fly (i.e. not part of static menus, etc.). To translate, simply click on the first source text-string in the first context, enter an appropriate translation, and press 'Control+Enter' to advance to the next string.

Some strings will contain HTML tags, like so:

Size<br /><i>in pixels</i>

In this case, only change the text and leave the HTML tags as they are. So, for a Dutch translation this would become:

Grootte<br /><i>in pixels</i>

Also, some strings contain wildcards, like so:

Tell me more about the %s item

These %s (and %d, %f, etc.) wildcards are blanks that are filled in on-the-fly by OpenSesame. Please respect these (removing a wild-card will crash the program!) and try to build an appropriate translation around them. So, for a Dutch translation this would become:

Vertel me meer over het %s item

Step 4: Compile your translation to .qm and test it

OpenSesame doesn't use the .ts file directly, but requires a file in .qm format. You can create this file easily from within Qt Linguist by selecting 'File -> Release as'. Create a .qm file with the same name (except for the extension) as the original file, and place it in the resources/locale subfolder of the OpenSesame folder. So, for example, if you're working on a French translation, your original source file would be resources/ts/fr_FR.ts and your compiled file would be resources/locale/fr_FR.qm.

Once you have compiled your translation file to .qm format and placed it in the resources folder, run OpenSesame with your new locale as described here.

Step 5: Save and submit your translations

Send by e-mail

Once you are satisfied with your translations, save the translations.ts file under a new name and send it to

Submit through GitHub

You can also submit (and update) your translation via GitHub. First, add your translation to your fork of OpenSesame, as resources/ts/ll_RR.ts, where ll corresponds to the language and RR to the region. For example, en_US is US english, fr_FR is French, and zh_CN is Chinese. You can find a list of valid regions and languages here. Next, submit a pull request to have your translation included in OpenSesame.

Updating an existing translation

The process to update an existing translation is similar to that described above for creating a new translation. The crucial difference is that you don't start with resources/ts/translatables.ts, but with a non-blank translation file, such as resources/ts/fr_FR.ts.