The kids are learning Mandarin through Pimsleur audio lessons, which focus on common conversational topics rather than reading and writing. I wasn't sure if the curriculum would be too advanced for them so I told them we'd do each lesson multiple times so they could gain familiarity at an easier pace. But I wasn't sure if the repetition would bore them.
Thankfully, any boredom in hearing the same 30-minute lesson over and over has been offset by the noticeable mastery they are getting over the words and phrases each successive time they do the lesson. We listen to the audio over dinner and each time they hear it they are able to follow more and more easily.
We bought 120 30-minute lessons, and we've gone through one so far, five times in a row. I think they won't need five reps for each lesson but we'll see. I'm glad they're seeing progress and slowly but surely maybe they can say they're bilingual, at least conversationally, which would be cool.