Genetic Descent/continuity & convergence

[Ante Aikio]

On Sat, 23 Jun 2001 X99Lynx at aol.com wrote:

> Is there a more "pithy" answer to why there can only be one genetic ancestor
> than this one?

Genetic relationship is defined in terms of continuity. E.g., there is
continuity between the linguistic systems of present-day English and
Proto-Germanic. There is no continuity between English and French, despite
the fact that English has borrowed massively from French: i.e., if we
could go backwards in time, we could observe English gradually becoming
Proto-Germanic; but at no point would it become French.

Could there, then, be a case where a language becomes not a different
language, but rather *two* different languages, when the film is run
backwards?

There is one especially interesting type of case, which could
(erroneously?) be seen as a counterexample. I know only a couple of
examples, an especially interesting one being Sea Sami.

Sea Sami is one of the three main dialect groups of North Sami (it is a
dialect group, not a separate language; the North Sami dialects are 95+%
mutually intelligeble). North Sami belongs taxonomically to western Samic,
which shows several innovations distinguishing it from Eastern Samic, the
most important ones here being two sound shifts: Western Samic underwent
the changes *NN > *TN between vowels (i.e., *nn > *tn, *mm > *pm etc.) and
*S (= sh) > *jh before *k, *t or *n (unusual sound shifts, once again),
whereas Eastern Samic preserved the original forms. The sole exception to
these Western Sami innovations is Sea Sami, which has preserved the
original nasal geminates, and only very recently (in the 19th century)
underwent the shift *S > *jh, which is prehistorical in the other
languages / dialects and presumably must be dated to Proto-Western-Samic.
This, and other evidence as well, suggests that Sea Sami was originally no
dialect of North Sami, but rather a separate language belonging to the
Eastern group. But as its speakers spread west along the Scandinavian
coast, it became subject to so strong North Sami influence that it
ultimately coalesced with it, while still preserving a couple of archaic
features indicating its genetic origin.

Sea Sami has sometimes been presented as an example of a language /
dialect having two genetic ancestors (i.e. North Sami and
Proto-Eastern-Samic, both of which, of course, ultimately derive from
Proto-Samic). However, at least in my view, this interpretation can
be criticized: there is no continuity between (Proto-)North Sami
and Sea Sami, so it is genetically Eastern Samic. Synchronically, however,
it is now a dialect of North Sami, but this seems to be merely a result of
convergence (borrowing included under the term "convergence" here).

There are also similar cases in Finnic, but the details are far more
complicated. E.g., Finnish does not represent a single branch in the
Proto-Finnic family tree, but is the result of convergence and ultimate
coalescence of many dialects belonging to at least two taxonomically
distinct branches. Even today, there is not a single isogloss that defines
Finnish as a whole as opposed to the rest of Finnic. The case of South vs.
North Estonian is somewhat similar: South Estonian has preserved several
archaic forms in several cases where *all* the other Finnic
languages/dialects have an innovative form; this concludes that the
primary genealogical dichotomy in Finnic is South Estonian vs. all the
rest (including North Estonian). However, due to convergence, South and
North Estonian are today mutually intelligible to a fair degree, but the
mutual intelligibility of Estonian and Finnish is practically nonexistent,
disregarding some very simple expressions.

I'd be most interested in hearing how typical these kinds of convergence
scenarios between closely related languages are (I suppose there must be
plenty of examples elsewhere), and opinions on how they should be
taxonomically interpreted.

Regards,
Ante Aikio