Clarification re 'velar softening'

> Hi Professor Ohala,
> In lecture on Tuesday, you demonstrated how a velar stop [k]
> sounded very similar to a [t] when you filtered out the mid
> frequency is filtered out.  Is this what happens in speech?
> Does that mid-frequency get filtered out to the listener?  Is
> there something that makes it particularly susceptible to
> that?  Since it doesn't seem like an all too uncommon change.
> Do you know if this is similar to what happened in English?  I
> was told there was some sort of change, and words like 'chin'
> in English are 'Kinn' in German and that that was a regular
> sound change in an earlier stage.  Did the [k] first become a
> [t] and then an affricate?  Or how does the alveolar affricate
> come about or is theorized to come about?
> Thank you!
> Stephanie

Stephanie,

Some good questions.  Thank you for giving me the opportunity to clarify.

It is not so much that in natural speech there is some process which
filters out the mid-frequency peak but rather that through inattention,
perhaps masking noise, etc., this spectral peak can be missed.  (And keep
in mind the mid-frequency spectral peak is primarily found ONLY when the
velar stop is released into a high front vowel; it is not the same with
other vowels.)  Crucial to my story is that this spectral peak is pivotal
to the differentiation of /ki/ from /ti/ and that if it is overlooked the
percept is that of /ti/.  You are right that the development of /ti/ to
/tshi/ (the affricated version) is a separate, subsequent, change. (I
explained earlier how aerodynamic factors can lead to turbulence when air
is forced at high velocity through a narrow constriction such as is
created in the transition between /t/ and /i/.)   And we find some cases
of this change that just involve change of place and do not involve
affrication.

JJO