Problem with size limits and ebooks

Is there a way to increase the word limit on lessons?
I am trying set up one lesson per chapter so that I can attach an audio file, so that I can read and listen within the same lesson. However, I run into the issue of being limited to 4000 words per lesson when I try to cut and paste the entire text of a chapter.

(Example of a book I am importing:

Le Parfum de la dame en noir/7 - Wikisource)

Sorry, but at the moment it’s not possible to increase the limit.