Parsing Three German Treebanks: Lexicalized and Unlexicalized Baselines
نویسندگان
چکیده
Previous work on German parsing has provided confusing and conflicting results concerning the difficulty of the task and whether techniques that are useful for English, such as lexicalization, are effective for German. This paper aims to provide some understanding and solid baseline numbers for the task. We examine the performance of three techniques on three treebanks (Negra, Tiger, and TüBa-D/Z): (i) Markovization, (ii) lexicalization, and (iii) state splitting. We additionally explore parsing with the inclusion of grammatical function information. Explicit grammatical functions are important to German language understanding, but they are numerous, and naı̈vely incorporating them into a parser which assumes a small phrasal category inventory causes large performance reductions due to increasing sparsity.
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