This was recently followed by (Matsuzaki et al., 2005;Petrov et al., 2006) who introduce state-of-the-art nearly unlexicalized PCFG parsers.
as discussed above, all state-of-the-art published methods rely on lexical features for such tasks (Zhang et al., 2001;Sha and Pereira, 2003;Finkel et al., 2005;Ratinov and Roth, 2009).