Generating a controlled language

This paper argues for looking at Controlled Languages (CL) from a Natural Language Generation (NLG) perspective. We show that CLs are used in a normative environment in which different textual modules can be identified, each having its own set of rules constraining the text. These rules can be used as a basis for natural language generation. These ideas were tested in a proof of concept generator for the domain of aircraft maintenance manuals. 1 W h a t is a C o n t r o l l e d Language? Controlled Languages (CLs) result from a growing concern about technical documentat ion quality and translation, be it human or automatic. A CL consists of a glossary and of writing rules for the linguistic aspect of the documentation. These rules are given as recommendations or prohibitions for both the lexicon and the grammar. Currently, most CLs are varieties of "controlled English" which derive froth the Caterpillar Tractor Company Fundaveloped for CL users, the best known being conformity checkers/controllers such as AlethCL or SECC (CLA, 1996). A wri ter expects that the checking tool should not only detect errors but also propose a CL conformable expression. A. Nasr (Nasr, 1996), who worked on the problem of CL refornmlation, underlines the difficulties of this task. Reformulation cannot make any hypotheses abou t the conformity of the input sentences, and therefore must deal with a wider variety of lexico-syntactical constructions than those allowed in a CL. Some instances of noncompliance are relatively easy to detect but much more difficult to correct: for example, sentences that are longer than the prescribed number of words. So there is little hope that human writers will ever produce documentation complying strictly with a CL even with the help of a conformity checker. We argue that it may be more promising to use NLG technology for generating doc.umenta t ion in. CL instead of analyzing it afterwards, as it is the case with a conformity checker. Few researchers have looked at CLs mental English tha t vi~. .elab0rated. in the S~: ...... from-:a~-~generation po in t of view.. (Nasr, 1996; ties (Scheursand Adriaens, 1992). However CLs Hart ley and Paris, 1996); but we think that are presently being defined for German, Swedish and French. Technical writers find it difficult to comply with the writing rules of a CL which are often hard to justify (CLA. 1996). For them, a CL is seen as an additional constraint on an already complex task. This is why tools have been de" Work done while at the Adrospatiale Research Center there are very compelling reasons for taking a generation perspective, in addition to the advantages of NLG for CLs that will be presented in section 3: * As CLs can be viewed as linguistic specifications for human beings, it seems natural "to, .consider them 'a:s specifica'tkms for the linguistic component of an NLG system.