Main natural language processing levels, from word tokenization to semantics. The different processing layers for a given example sentence are shown here. This example is based on the output generated by the GENIA tagger: DT, determiner; IN, preposition or subordinating conjunction; JJ, adjective; NN, Noun (singular or mass); NNS, Noun (plural); VBZ, Verb (third person singular present). The B/I/O terminology refers to begin phrase (B), internal to phrase (I), and outside of phrase (O).
Krallinger et al. Genome Biology 2008 9(Suppl 2):S8 doi:10.1186/gb-2008-9-s2-s8