Meredith, thanks so much for asking your question. I will provide some insights that come from my experience as a classroom teacher and hopefully we will have other share their practices to meet the needs of ELL students. First, I would encourage students to change default language in their account settings. Here is a guide that shows you the step by step process for this. How do I change the language preference in an account? This will allow students to experience the Canvas user interface in their native language. In addition, when creating assignments I often allowed for media submissions for ELL students. This allowed the student to submit the assignment on paper but also provide a verbal description depending on their strength, I would grade the better of the two.
Another option, is to use some technology from Google that allows students to provide their answers verbally in their native language and then use Google Translate so that I could read it. Here is a you tube video on what I mean, Transcription: Best Free Way to Automatically Transcribe Video (Audio to Text) - YouTube . Since Google Drive is now an integration with Canvas that process becomes much easier.
I have also differentiated assignments. You can use the ability in Canvas to create assignments for individuals that others would not see. So any assignment with an ELL accommodation, I would assign to that individual student or subset of students. Here is a guide on that How do I assign an assignment to an individual student?
Finally, I would suggest checking out some apps that can be integrated. Just off hand I can think of Quizlet. You or the student can practice language acquisition by creating these flashcards that also have audio attached to them. Another app that can be integrated with Canvas is TextReader. It lets teachers create blocks of text where students can click any word in the text and retrieve an inline definition of the word. Rosetta stone can be integrated as well but that is a pay for app.
Hope these help, I am interested in seeing what others have to add to this topic.