Middle Dutch is a collective name for a number of closely related West Germanic dialects (whose ancestor was Old Dutch) which were spoken and written between 1150 and 1500. There was at that time as yet no overarching standard language, but they were all mutually intelligible.In historic literature Diets and Middle Dutch (Middelnederlands) are used interchangeably to describe this whole group of dialects from which later standard Dutch would be derived.