It is likely he wrote such a work; one suggestion is that the work was such a bad piece of writing it was lost, but if that had been the case, Chaucer would not have mentioned it.
Чосер был первым, начавшим писать на родном языке и прозой, а не по-латыни (например, «The astrolab» — трактат, написанный им в 1391 г. для его сына).