Re: [tied] Non-correspondence of voiceless stops in several IE lang

>Latin "quinque", shows a
>change of the initial p to kw. ...
>I would like to know if this change of initial p to k is common and
>whether some linguistic rule could be applied to it.

Yes: the rule is that the sequence *p...qu" was changed to "qu...qu" in
Italic and Celtic.
Several words show this, e.g
*pekW "cook" appears as Latin coquo
*perkWu- "oak" gives Latin quercus.
*ponkWu "all" gives Latin cunctus (if we are interpreting Hittite pankus
"all" correctly)

Peter