How to translate the toolbar into multiple languages?

Hello dear members of LibreOffice support,

I want to translate an application based on Macros developed in French to include default English for our GNU/Linux distribution.

I've already found how to translate dialog boxes into multiple languages, and have default English: https://help.libreoffice.org/Basic/Tr...

I can not find on the Internet how to have the translation of the text of the icons of a toolbar in English by default, and also in French according to the language selected by the user.

My files for defining the toolbar are called custom_toolbar_XXXX.xml, and are in this format:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE toolbar:toolbar PUBLIC "-//OpenOffice.org//DTD OfficeDocument 1.0//EN" "toolbar.dtd">
<toolbar:toolbarseparator/>
<toolbar:toolbaritem xlink:href="vnd.sun.star.script:Standard.Module6.gerer_fond_ecran?language=Basic&amp;location=application" toolbar:text="Ajouter ou modifier une image de fond "/>
</toolbar:toolbar>


Is it possible to put a language attribute in these files to specify on which language the translation carries?

If not, where can we find the syntax of the toolbar.dtd format?