To enable translations for a report, translation functions need to be called from a template, using a <t t-call> element with the t-lang attribute.
The t-lang attribute should evaluate to a language code, such as es or en_US. It needs the name of the field where the language to use can be found.
One way to do this is by using the current user's language. For this, we define an outer translation report that calls a report to translate, setting the source for the language in the t-lang attribute:
<report id="action_library_book_report_translated"
string="Translated Library Books"
model="library.book"
report_type="qweb-pdf"
name="library_app.report_library_book_translated"
paperformat="paperformat_euro_landscape"
/>
<template id="report_library_book_translated">
<t t-call="library_app.report_library_book_template"
t-lang="user.lang" />
</template> In this case, each book...