Ocsigen Start uses Ocsigen-i18n for internationalizing your app. Ocsigen-i18n defines a PPX syntax extension for automatically selecting language-dependent text for each user. The user can choose his preferred language from the settings page. By default the browser's language is used.
Write your translations (as tab-separated-values) in file assets/osdemo_i18n.tsv. File osdemo_i18n.eliom is generated automatically from this file.
Have a look at the OCaml code of this page to discover some features of the module Ocsigen-i18n.
To make your life easier, the entries used for this whole demo sub-site have been split into their own file assets/osdemo_Demo_i18n.tsv. When you feel ready to make this project your own, you can freely delete all the demo_ files, and assets/osdemo_Demo_i18n.tsv.