Rate of Change: A Closer Look

[Rich Alderson]

On 23 Jun 2001, Steve Long wrote:

> Average rates of change are based on multiple occurrences.  You get an
> average by finding the same changes in different languages and averaging the
> time they took.

Definitionally difficult:  Two languages cannot undergo "the same changes", so
substitute "similar" for "same".  Then be prepared to argue the validity of the
similarity you propose to measure and average.

> So pick a *set* of changes that has occurred in at least five, preferably ten
> languages, and the time it took for each of them to occur historically.

Who gets to decide how long the changes took?  Or are you restricting the
sample only to historically attested changes?  In that case, are you prepared
to accept the results if they contradict your view of the prehistoric spread of
the Indo-European languages?  Or will you aver that unattested (that is to say,
unwitnessed) changes must have happened at a different rate?

> If Time consistently produces a MEASURABLE amount of AVERAGE change in some
> specific feature of a number of historical languages, that can be validated
> statistically.

Suppose that no specific feature ever shows a correlatable average rate of
change?  Suppose that it is instead entire systems that change at a comparable
rate, with no particular change required?  What then?

								Rich Alderson