Welcome to this site. The site is primarily in Englisch with the main reason that we also have a lot of students in The Netherlands. And with Google Translate you can put it back in Dutch.
I hope my information is understandable and useable, and I will claim that I am not the founder of Nuttx!!!! This blog talks about the NuttX RTOS with a link to the original project!
Source: http://www.nuttx.org/
I am primarily focussing on the STM32 platform, but other MCU’s can come across.