Apparatus and method for natural language processing

A natural language processing apparatus for achieving a syntax analysis and/or a syntax generation by using natural language patterns with language name, syntax pattern name (left side) and pattern component (right side) list of an source language pattern and a target language pattern, the natural language processing apparatus comprising:

• a pattern dictionary having stored therein natural language patterns in pairs that include the source language pattern and the target language pattern, each pair being formed in a string with, at least a language name, a pattern name given as a left side member and a pattern component given as a right side member, the source and target language patterns being stored in advance and having a feature indicated by feature information in various information used for a translation, which is present in the left side member and/or the right side member of a pattern, a feature restriction indicating a condition on information held in the feature and a central element information, appended to a central element, prescribing a central pattern element in a feature restriction or a feature propagation on the left and/or the right side;
• a dictionary reference part that extracts at least one source language pattern and target language pattern from the pattern dictionary to be used in syntax analysis processing and syntax generation processing;
• pattern inspection means for inspecting also the extracted source language pattern and target language pattern to determine whether or not the right side member of the source language pattern conforms to a tree structure of-net based upon the feature restriction during the syntax analysis processing and to determine whether or not the left side member of the target language pattern conforms to a tree structure based upon the feature restriction during the syntax generation processing;
• and
• pattern application means for applying the natural language patterns to the tree structure if the natural language patterns meet the tree structure, for propagating the feature information held by the central element in the right side member of the source language pattern to a node in the tree structure equivalent to the left side member and adding the feature information in the left side member as a node in the tree structure during syntax analysis processing when the right side member of the source language pattern conforms to the tree structure, and for adding the feature information present in the left side member of the target language pattern to a node in the tree structure equivalent to the central element in the right side member during syntax generation processing when the left side member of the target language pattern conforms to the tree structure.