For the BNC sampler corpus the enriched C6 tagset was used which has over 160 tags. Grammatical annotation at Lancaster originated with Geoffrey Sampson's manual parsing of the Lancaster-Leeds Treebank. This simplified grammatical analysis uses an even smaller set of grammatical categories. Key to Parsing Symbols . Square brackets enclose constituents above word level.
Unlabelled brackets indicate a constituent for which no label is provided by the annotation scheme.
Word sense tagging Beyond grammatical annotations, semantic annotation is an obvious next step. The tags for each entry in the lexicon and idiom list are arranged in general rank frequency order for the language. This combination of general frequency data and promotion by domain, together with heuristics for identifying auxiliary verbs, considerably reduces mistagging of ambiguous words. In this fragment, the text is read downwards, with the grammatical tags on the left, and the semantic tags on the right. Words belonging to closed classes, as well as proper nouns, are marked by a tag with an initial Z, and set aside from the statistical analysis.