A method for specifying equivalence of language grammars and automatically translating sentences in one language to sentences in another language in a computer environment. The method uses a unified grammar specification of grammars of different languages in a single unified representation of all the individual grammars where equivalent production rules of each of the grammars are merged into a single unified production rule. This method can be used to represent the equivalence of computer languages like high level language, assembly language and machine language and for translating sentences in any of these languages to another language.