Processing Unknown Words in HPSG

The lexical acquisition system presented in this paper incrementallyupdates linguisticproperties of unknown words inferred from their surrounding context by parsing sentences with an HPSG grammar for German. We employ a gradual, informationbased concept of "unknownness" providing a uniform treatment for the range of completely known to maximally unknown lexical entries. "Unknown" information is viewed as revisable information, which is either generalizable or specializable. Updating takes place after parsing, which only requires a modified lexical lookup. Revisable pieces of information are identified by grammar-specified declarations wlfich provide access paths into the parse feature structure. The updating mechanism revises the corresponding places in the lexical feature structures iff the context actually provides new information. For revising generalizable inlbrmation, type union is required. A worked-out example demonstrates the inferential capacity of our imp...

• Type: Conference
• Year: 1998
• Where: ACL
• Authors: Petra Barg, Markus Walther
• Keywords: ACL 1998, ACL 2007, Lexical, Modified Lexical Lookup, Unknown Lexical Entries