Abstract: The invention concerns a computer system for speech recognition with a word table and a triphone table in its memory. In response to a new word not contained in the word table and which is encountered by the computer system during recognition of an unknown spoken text, the fenemic baseform of this new word may be synthetically produced with the aid of a triphone table. For this purpose, the new word is decomposed into triphones, and the fenemic sequences associated with the individual triphones are read from the triphone table. The fenemic sequences are concatenated according to the phonetic baseform of the new word such that the fenemic baseform of the new word is obtained.