Controlled natural language

Controlled natural languages (CNLs) are subsets of natural languages, obtained by restricting the grammar and vocabulary in order to reduce or eliminate ambiguity and complexity. Traditionally, controlled languages fall into two major types: those that improve readability for human readers (e.g. non-native speakers), and those that enable reliable automatic semantic analysis of the language.

The first type of languages (often called "simplified" or "technical" languages), for example ASD Simplified Technical English, Caterpillar Technical English, IBM's Easy English, are used in the industry to increase the quality of technical documentation, and possibly simplify the (semi-)automatic translation of the documentation. These languages restrict the writer by general rules such as "write short and grammatically simple sentences", "use nouns instead of pronouns", "use determiners", and "use active instead of passive".

The second type of languages have a formal logical basis, i.e. they have a formal syntax and semantics, and can be mapped to an existing formal language, such as first-order logic. Thus, those languages can be used as knowledge-representation languages, and writing of those languages is supported by fully automatic consistency and redundancy checks, query answering, etc.

Languages

Existing logic-based controlled natural languages include:

• Attempto Controlled English
• Common Logic Controlled English (CLCE)
• Metalog's Pseudo Natural Language (PNL)
• Ordnance Survey Rabbit
• Processable ENGlish (PENG)
• Semantics of Business Vocabulary and Business Rules

Other existing controlled natural languages include:

• ASD Simplified Technical English (AeroSpace and Defence Industries Association of Europe--formerly AECMA)
• E-Prime
• Gellish
• Newspeak, the fictional language in the dystopia novel 1984 by George Orwell, is a controlled natural language as well as a semi-constructed language.
• Uwe Muegge's Controlled Language Optimized for Uniform Translation (CLOUT)
• Voice of America's Special English

See also

• Constructed language
• Knowledge representation
• Natural language processing

References

External links

• Controlled Natural Languages (Macquarie University)
• Overview of Controlled English and HyperSTE, customizable Controlled English checker
• Simplus – Simplified English Checker
• acrocheck – Customizable controlled language checker for many authoring environments
• PERMIS Policy Editor uses controlled English in its user interface