Dutch dialects and regional languages are not spoken as often as they used to be. Recent research by Geert Driessen shows that the use of dialects and regional languages among both Dutch adults and youth is in heavy decline. In 1995, 27 percent of the Dutch adult population spoke a dialect or regional language on a regular basis, while in 2011 this was no more than 11 percent. In 1995, 12 percent of the primary school aged children spoke a dialect or regional language, while in 2011 this had declined to 4 percent. Of the three officially recognized regional languages Limburgish is spoken most (in 2011 among adults 54%, among children 31%) and Dutch Low Saxon least (adults 15%, children 1%); Frisian occupies a middle position (adults 44%, children 22%).

What organization researched the use of regional Dutch dialects and found their usage declining?