Bilingual documents: unable to declare language on foreign language passages

[Ovgodd]

Observed behavior

When a document contains passages written in two different languages, it is not possible to declare the language on each portion of text. Passages in a foreign language cannot be tagged with the corresponding lang attribute, and passages in French cannot be explicitly assigned lang="fr" either.

Expected behavior

The editor must allow the user to define the language of a selected text passage, so that the lang attribute is applied to the corresponding HTML element with the correct language code (e.g. lang="fr", lang="en", lang="de", etc.). Language changes in a document must be reflected in the generated markup.

Steps to reproduce

Create a document containing passages in French and passages in another language.
Select a passage in a foreign language.
Look for an option to declare the language of this passage.
Observe that no such functionality is available.
Possible solution

Add a "Text language" option in the formatting menu or in a context menu, which applies the lang attribute to the or block element surrounding the selection:

Before:

Voici un exemple. This is an example.

After:

Voici un exemple. This is an example.

Impact

A blind user navigating with a screen reader reads a bilingual document. The screen reader renders passages in a foreign language with the French speech synthesis voice, producing incorrect and incomprehensible pronunciation. The user cannot access content in a foreign language under normal reading conditions.