To train a parser.chunking.Parser, both from the CLI or using the API, the headRule class used is always the parser.lang.en.HeadRules class. This class performs two functions:
1. It hardcodes the headrules for Noun Phrases.
2. It reads a headRules file to load the headRules for the rest of the constituents.
While trying to train parsers for other languages, it is now only possible to train with the lang.en.HeadRules class.