1. A system for translating phrases from a first language into a second language, comprising: input means for accepting an input phrase in the first language; a store holding a collection of phrases in the second language; characterization means connected to said input means for determining which phrase of the collection corresponds to the input phrase, and to control the output of that phrase; and output means responsive to the characterization means for outputting the determined phrase in the second language; wherein the characterization means comprises means for recognizing in the input phrase the presence of at least one keyword or keyword parts of a predetermined set of keywords or keyword parts, the number of members in the set of keywords being smaller than the number of phrases in the collection, and to select, in dependence on those recognized keywords or keyword parts, a stored phrase from the collection.