If the medium is speech the whole repertoire of learned vocabulary and meaning is exploited. In order to maintain a reasonable intelligibility the bandwidth should not be below three kHz, but higher bandwidth leads to a better quality. In a teleconference environment speech is generated by the participants, compressed, transmitted and uncompressed for presentation. Speech also can be used as interface machine-man interface. Recorded words or sentences can be played to inform the user about the status of the machine. Also information stored in textual form an be transformed into speech by the means of sophisticated synthesis algorithms. Hardware and software for this purpose is commercially available.
Another interesting application of speech is the use of speech inside of text documents. A lot of text editors offer to append non textual items like pictures and sound documents. Some tools for electronic mail support sound attachments, which might be a speech recording done by the sender. Some text editors allow to make annotations in text. At the position of the annotation an icon will appear. If the icon is activated either a textual or spoken annotation will appear.