The language is English, as it is for all lessons except the ones I teach, ie Religious education. A bit ironic, as most other teachers are Tanzanians. I think it's because RE deals with issues close to the heart, so it helps if it is in a 'heart language'. The syllabus is written in Kiswahili, and is very helpful.
In the background you can see the classrooms, a cylindrical rainwater harvesting tank, and the corners of a new classroom being built by a visiting team from a UK school in partnership with St Michael's, Kilolo.