This module translates the parse tree or parse tree fragments into a semantic structure or logical form or event frame. All of these are basically explicit representations of predicate-argument and modification relations that are implicit in the sentence. Often lexical disambiguation takes place at this level as well. Some systems have two levels of logical form, one a general, task-independent logical form intended to encode all the information that is in the sentence, and the other a more specifically task-dependent representation that often omits any information that is not relevant to the application. A process of logical-form simplification translates from one to the other.
The method for semantic interpretation is function application or an equivalent process that matches predicates with their arguments. The rules are acquired manually.
There are a number of variations in how the processing is spread across Modules 4-7. It may be as I have outlined here. The system may group words into phrases, and then phrases into parsed sentences, and then translate the parsed sentences into a logical form. The more traditional approach is to skip the first of these steps and go directly from the words to the parsed sentences and then to the logical forms. Recently, many systems do not attempt full-sentence parsing. They group words into phrases and translate the phrases into logical forms, and from then on it is all discourse processing. In a categorial grammar framework, one goes directly from words to logical forms.