Well, it parses natural language. In linguistics, or syntax to be precise, there are different ideas on how to build syntax trees. The most common is Dependency Grammar, basically just a tree where every word points to the word it refers to (the adjective to the noun, the subject and the object to the verb, the verb is the root). I applied this to a different syntax theory called Role and Reference Grammar. You can google the latter, if you want to look into neural parsers in general, stanfordNLP has modules for python and I think online tools as well and stuff.