Learning Senna src
Quite interestingly, the implementation was in ANSI C. Should be very efficient
Senna Overview
SENNA is a software distributed under a non-commercial license, which outputs a host of Natural Language Processing (NLP) predictions: part-of-speech (POS) tags, chunking (CHK), name entity recognition (NER), semantic role labeling (SRL) and syntactic parsing (PSG).
SENNA is fast because it uses a simple architecture, self-contained because it does not rely on the output of existing NLP system, and accurate because it offers state-of-the-art or near state-of-the-art performance.
SENNA is written in ANSI C, with about 3500 lines of code. It requires about 200MB of RAM and should run on any IEEE floating point computer.