Using Machine-Learning to Assign Function Labels to Parser Output for Spanish

Data-driven grammatical function tag assignment has been studied for English using the Penn-II Treebank data. In this paper we address the question of whether such methods can be applied successfully to other languages and treebank resources. In addition to tag assignment accuracy and f-scores we also present results of a task-based evaluation. We use three machine-learning methods to assign Cast3LB function tags to sentences parsed with Bikel's parser trained on the Cast3LB treebank. The best performing method, SVM, achieves an f-score of 86.87% on gold-standard trees and 66.67% on parser output - a statistically significant improvement of 6.74% over the baseline. In a task-based evaluation we generate LFG functional-structures from the functiontag-enriched trees. On this task we achive an f-score of 75.67%, a statistically significant 3.4% improvement over the baseline.

• Type: Conference
• Year: 2006
• Where: ACL
• Authors: Grzegorz Chrupala, Josef van Genabith
• Keywords: ACL 2006, ACL 2007, Function Tags, Tag Assignment, Task-based Evaluation