In sum, various symbolic and statistical techniques have been developed to improve the efficiency of grammar-based surface realisation.
statistical systems using supertagging require the existence of a treebank in an appropriate format while the purely symbolic systems described in (Carroll and Oepen, 2005;Gardent and Kow, 2005;Koller and Striegnitz, 2002;Gardent and Perez-Beltrachini, 2010) have not been evaluated on large corpora of arbitrarily long sentences such as provided by the surface realisation (SR) task (Belz et al., 2011).