In my search for PBL in a diverse classroom I came across a video that was looking at the effectiveness of PBL in an ELL setting. The video shows a biology classroom that is using hands on projects to help students have understanding of the content. As the students work in small groups, the teacher has encouraged his students to use their native languages when they can, while using english in the large group setting.
The important point I saw from this video was the hands on aspect of PBL for students. No matter their language, if students are able to have hands on experiences, they are going to understand the content on a greater level than simply taking notes on a screen.