A couple decades ago when I was in middle school in Colorado, I was briefly taught to diagram sentences using the Reed-Kellogg system. I have heard that the practice of teaching sentence diagramming in schools in North America has fallen out of favor. But at Youtube, one finds numerous videos instructing one how to produce them. I am currently writing an introduction to a translation of Lucien Tesnière's The Elements of Structural Syntax. Tesnière's stemmas are similar to the Reed-Kellogg diagrams in a major respect. I am therefore interested in learning about the extent to which the Reed-Kellogg diagrams are still taught in schools in North America and elsewhere.
Does anyone know the extent to which the art of diagramming sentences is still taught in schools today? Is the practice gaining or losing? Thanks.