Local time reversal and speech comprehension

It is widely appreciated that, when speech is time reversed, it becomes incomprehensible but it continues to sound rather speech-like, not unlike the sound of a foreign language. However, as was discovered by Saberi and Perrott in 1999, if speech is cut into small strips and each strip is short enough, then speech does remain comprehensible. The sound examples on this page illustrate this effect. The sounds reversed in 200 or 100 ms wide strips are normally completely incomprehensible, while with 50 ms wide strips some listeners start to understand the odd word, and a time reversal of 20 ms wide strips does not affect comprehension at all.

200 ms time reversal:

100 ms time reversal:

50 ms time reversal:

20 ms time reversal:


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