A 40 bps speech coding scheme

We describe a method and an implementation for producing a highly compressed representation of speech, in the order of 40 bps. This compression method uses a speech recognition engine to analyze the speech signal at the morphological level, i.e. the words. The words are then coded using a word-level text compression mechanism. After decompression, the speech message is recovered using text-to-speech synthesis. We report experimental results of our implementation. In particular, we observed that human listeners were able to recover from errors introduced by the speech recognition engine, and that the human perceptual errors were highly dependent on the content of the messages, especially regarding familiarity with the topic.