17. A system for translating voiced phrases from a first language into a second language, comprising: input means for accepting a voiced input phrase in the first language; a store holding a collection of phrases in the second language; characterization means comprising speech recognition means and connected to said input means for determining which phrase of the collection corresponds to the voiced input phrase and to control the output of that phrase; output means responsive to the characterization means for outputting the determined phrase in the second language; and wherein the characterization means comprises means for recognizing in the voiced input phrase the presence of at least one keyword or keyword part 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.
17. A system for translating voiced phrases from a first language into a second language, comprising: input means for accepting a voiced input phrase in the first language; a store holding a collection of phrases in the second language; characterization means comprising speech recognition means and connected to said input means for determining which phrase of the collection corresponds to the voiced input phrase and to control the output of that phrase; output means responsive to the characterization means for outputting the determined phrase in the second language; and wherein the characterization means comprises means for recognizing in the voiced input phrase the presence of at least one keyword or keyword part 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. 18. A system as claimed in claim 17 in which the speech recognition means applies a first set of predetermined keywords to determine to which phrase or group of phrases, if any, from said collection of phrases the voiced input phrase corresponds, and in the case that the voiced input phrase is found to correspond to an undetermined one of a group of phrases, the speech recognition means applies a second set of predetermined keywords to determine to which one of the group of phrases the input phrase corresponds.