In Flanders and the Netherlands, van Oostendorp is known as a contributor to Genootschap Onze Taal ("Society for our language").
He collaborates with Belgian copywriter Erik Dams to produce Taalpost, a thrice-weekly e-mailed newsletter on the topic of language in general and Dutch in particular.
Oostendorp received his BA in Dutch literature and linguistics from Leiden University in 1987.
To help disseminate linguistic knowledge, among other things, in 1996 he compiled a guide to help people create their own home pages on the Internet.
[4] He also held visiting lectureships at universities in Essex; Toronto; Amherst, Massachusetts; Tromsø, Trondheim, Verona and Barcelona.