The Linguistic String Project (LSP) natural language processing system has been developed as a domain-independent natural language processing system. Initially utilized for processing sets of medical messages and other texts in the medical domain, it has been used at the Naval Research Laboratory for processing Navy messages about shipboard equipment failures. This paper describes the structure of the LSP system and the features that make it transportable from one domain to another. The processing procedures encourage the isolation of domain-specific information, yet take advantage of the syntactic and semantic similarities between the medical and Navy domains. From our experience in transporting the LSP system, we identify the features that are required for transportable natural language systems.

Sublanguages differ from each other, and from the "standard language", in their syntactic, semantic, and discourse properties. Understanding these differnces is important if we are to improve our ability to process these sublanguages. We have developed a semiautomatic procedure for identifying sublanguage syntactic usage from a sample of text in the sublanguage. We describe the results of applying this procedure to three text samples: two sets of medical documents and a set of equipment failure messages.

Methods of text compression in Navy messages are not limited to sentence fragments and the omissions of function words such as the copula be. Text compression is also exhibited within "grammatical" sentences and is identified within noun phrases in Navy messages. Mechanisms of text compression include increased frequency of complex noun sequences and also increased usage of nominalizations. Semantic relationships among elements of a complex noun sequence can be used to derive a correct bracketing of syntactic constructions.