jonny5 is a reference to the movie Short Circuit; the kazoo app tracks limits and balances for accounts and does authorization for resource-consuming calls. In other words, it short-circuits calls that are not authorized :p
For numbers, check out https://docs.2600hz.com/dev/doc/internationalization/numbers/
You'll probably want alternative prompt languages too: https://docs.2600hz.com/dev/doc/internationalization/prompts/
While most of the 2600Hz team is US-based we do have a number of devs outside the US as well as a group of community members outside the US too. We all want KAZOO to be a proper platform for any region of the world. That said, we also know we have blind spots of how telecom is done everywhere so any feedback you have which can be incorporated into the project for everyone to take advantage of, is greatly appreciated.
Also, when you feel you need to look at code or the docs aren't sufficient, ask here in the forums - that's usually a good trigger for someone to take a stab at improving the documentation. You are always welcome to submit PRs for improved docs as well.