When translating a language course, be careful not to translate the words written in the language being taught!
For example, you have a french lesson commented in english :
« "Bonjour" means "Hello" »
If you want to translate the lesson into italian it will be :
« "Bonjour" significa "Buongiorno" »
In this example the french language is the taught language and the english and spanish languages are the languages used to comment the lesson. "Bonjour" is kept untranslated.