Here are some notes from a recent search for resources on automatic sentence diagramming. I was looking for code/software to diagram sentences automatically, ideally in python.
Also, as far as I can tell, linguists, grammarians, and English majors call sentence diagrams "Reed-Kellogg" diagrams. NLP and computer science types call the diagrams "parse trees" or "concrete syntax trees," and produce them (usually) using probabalistic context free grammars (PCFGs).
If you want code that just works, the Stanford Parser looks like the place to start. It's in java, but I'm sure that won't be too much of a problem, because you can call it from the command line.
Python's NLTK might also work, but there are lots of different parsers, and it's not clear whether and how much training they require.
There are various other software packages out there -- some of them online -- but I doubt they'd support much volume, and batching would be a pain.
Other Software & Code
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