> You may not understand their level, and may be unable to negotiate it due to vocabular barrier (people invent non-standard vocab all the time). Your oversimplifications may bear unintended consequences, etc. You must take that into account and create a plan to make it clear.

This isn't actually bad in all cases though. It's like learning about science in primary school. You're gonna get some things simplified in a way that might be considered incorrect by those who are experts, but without some base layer of understanding to bootstrap from, you won't be able to become an expert.