1. A speech converting device comprising: speech inputting means of inputting speech of a first language; speech recognizing means of recognizing said input speech; first extracting/displaying means of extracting and displaying one or plural word strings of said first language, said word strings corresponding to a result of said speech recognition; conversion object selecting means of, from said displayed word strings, selecting a word string which is expected to become an object of conversion to a second language; second extracting/displaying means of, when a whole or a part of said selected word string is specified, extracting and displaying candidates of a term which corresponds to contents of said specified whole or part of said selected word string; candidate selecting means of selecting one of said displayed candidates; and converting means of determining said object of conversion to said second language on the basis of said selected word string and said selected candidate, and of converting said determined conversion object to a speech language of said second language.