4. The method of claim 2 , further comprising pruning, at the computing device, the outer arcs to exclude arcs representing possible head-modifier dependency between words in the sentence separated by a distance greater than a second distance threshold before pruning the index set based on the augmented vine parsing algorithm.
4. The method of claim 2 , further comprising pruning, at the computing device, the outer arcs to exclude arcs representing possible head-modifier dependency between words in the sentence separated by a distance greater than a second distance threshold before pruning the index set based on the augmented vine parsing algorithm. 5. The method of claim 4 , wherein the second distance threshold is based on a determination of a longest head-modifier dependency distance observed in training data.