Re: Sound Change /bs/ > /f/ ?

Santiago Matías Feldman wrote:
>
> As the title suggests, my question is: Do you know if
> the sound change /bs/ > /f/ exists in any context?
It happens in my Gwr, though as a conlang that probably doesn't count....
>
> I'm asking this because I've noticed that my mother,
> being an educated speaker, tends to produce a /f/
> instead of /bs/ in words like "obstáculo" and
> "abstracto", which gives her Spanish language a very
> odd touch when pronouncing that kind of words,
> creating very rare clusters like /ft/.
Curious, but quite understandable.

In Gwr sound changes, it's handled by a transformation-type rule:

Structural Desc.: 1[+stop +labial +voi] 2[+cont -voi] ===>
Struc. Change:  1+2[+cont +lab -voi]
(somewhat simplified)

It could be handled step-wise too, just more rules needed.