This movie takes place in the East-Netherlands region of Twente, most of the dialogue is spoken in the regional language, Twents, and the director and principal cast all come form Twente.
In the original screenplay, Jan (Herman Finkers) spent only a brief time in the clinic for demented patients. Finkers greatly expanded the interaction between Jan and his fellow patients (which he found "both comedic and tragic"), based on his own experience with some of his own family members who suffered from Alzheimer's disease.
Herman Finkers was responsible for the dialogue in the Twents dialect. He said that the difficult part was finding a suitable Dutch translation for the subtitles, because the dialect allowed him to be much less subtle in the wording.
When director Johan Nijenhuis heard of the Czech comedy Teorie tygra (2016) from his colleague Pavel Marik, he was immediately interested in doing a Dutch remake. He approached comedian Herman Finkers, with whom he'd been wanting to work for a long time, for the main part. Finkers agreed on a few conditions: he wanted to rewrite the screenplay, have a say in casting (as it was his long-time wish to work with Johanna ter Steege), and be involved in the final cut. Finkers described his re-write as "renovating a farm by leaving the original facade and beams, but re-doing the masonry".