1. A method comprising: accessing a dependency grammar; pre-processing an input sentence to produce a sequence of tokens; transforming the dependency grammar into a context-free grammar that can be used to parse the sequence of tokens in no more than O(n 4 ) time, where n is the number of tokens in the sequence; using a parser to parse the sequence of tokens in accordance with the context-free grammar to provide an output; and post-processing the output produced by the parser to indicate dependencies in the input sentence according to the dependency grammar.