Jason,
There is partial support for Swahili in ka-lite. It's available as a 'beta' language pack for ka-lite, and can be added in the Admin user interface.
Most of the pure ka-lite user interface was translated (I arranged it and helped fund the work a year or so ago). However ka-lite depends on translations aimed at Khan Academy e.g. for the exercises. Again I funded some exploratory work in this area before realising that the effort needed was way beyond what I could support directly. There's a much longer and richer back story I can explain if you decide to actually get involved.
In terms of videos the best estimate is around 1200 videos were subtitled about 5 years ago by an organisation called Asante Africa (who work in both Kenya and Tanzania). However for whatever reasons it's hard to find / identify all these videos. There are (last time I checked) in the order of 400 to 500 known, tracked videos that are subtitled. You can see many of them via
sw.khanacademy.org and/or by searching for them on YouTube (which is where they're hosted). Do please sample some of the videos (and if you're not fluent in the Swahili used where you'd like to use the videos, please ask some people who are to assess the suitability of the videos - as you may know better than I do, there are major differences in the Swahili of different peoples in East Africa and some organisations have found the videos don't suit their context or needs.
Over the years various people have shown interest in helping with the translations. There are likely to be several initial hurdles to surmount e.g. getting access to the translation consoles, establishing effective working practices, etc. If you are willing I'm happy to spend time helping get you up to speed and I can introduce you to the various people who are interested and who've been involved over the last few years.
FYI I don't speak Swahili, I live in the UK, I support and help with projects in education in many countries and regions including Tanzania, Kenya, Uganda and Ethiopia, etc. I'm a private individual (not part of an NGO, company, government, etc) who's trying to help improve education using appropriate practices and technologies.
Ciao
Julian