Abstract. The specification language Attempto Controlled English (ACE) is a controlled natural language, i.e. a subset of standard English with a domain-specific vocabulary and a restricted grammar. The restriction of full natural language to a controlled subset is essential for ACE to be suitable for specification purposes. The main goals of this restriction are to reduce ambiguity and vagueness inherent in full natural language and to make ACE computer processable. ACE specifications can be unambiguously translated into logic specification languages, and can be queried and executed. In brief, ACE allows domain specialists to express specifications in familiar natural language and combine this with the rigour of formal specification languages.
Controlled natural language close to natural language is in essence a kind of formal language, such as ACE REF .