Re: Intelligibility of reversed speech, Why?

[=?X-UNKNOWN?Q?T=F3th_L=E1szl=F3?= <tothl@xxxxxxxxxxxxxxx>]

On Wed, 24 Jan 2001, Yadong Wang wrote:

> local time reversal does not destroy intelligibility,
>
Can somebody tell me how exactly the statement "transformation T does not
destroy the intelligibility of speech" is defined?? I think one should be
very careful with such a statement. My idea is that speech cues are
redundant. This means that after the removal of one cue the speech signal
may retain its intelligibility - under the given cirsumstance (e.g. quiet
environment). This does not necessarily mean that the removed cue would
not help intelligibility under different circumstances (e.g. in noise).
So I think that the statement "transformation T does not destroy
the intelligibility of speech" should be defined as "sentence X and
sentence T[X] has the same intelligibility UNDER ANY POSSIBLE
CIRCUMSTANCES". (Let's measure "same intelligibility" using some
well-defined psychoacoustic experiment). To put it an inverted way,
"transformation T DOES dicrease intelligibility if there is at least one
experimental setting in which the intelligibility of the transformed
signal is decreased compared to the original one."
I would apply this definition to the good old statement about the phase
deafness of the ear. Was it ever exhaustively and thoroughly examined that
phase information under no circumstances can serve as a cue and increase
intelligibility?
Any opinions? (and sorry for thinking as a mathematician, but I can't do
it any other way :-) )

               Laszlo Toth
        Hungarian Academy of Sciences         *
  Research Group on Artificial Intelligence   *   "Failure only begins
     e-mail: tothl@inf.u-szeged.hu            *    when you stop trying"
     http://www.inf.u-szeged.hu/~tothl        *