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--></style><title>Re: Atkinson on phoneme inventories in
Science</title></head><body>
<div><font face="Times New Roman" color="#000000">Atkinson argues for
the existence of two correlations in a global sample of phoneme
inventories: a correlation between size of phoneme inventory and
distance from Africa, and a correlation between size of phoneme
inventory and size of the population of the speech community. Atkinson
needs the latter, phoneme-population correlation to justify his
founder-effect explanation for the former correlation. The
phoneme-population correlation was also identified by Hay and Bauer
(2007). (Hay and Bauer also test Pericliev's [2004] data and found,
pace Pericliev, that the correlation is also strong in his sample [Hay
and Bauer 2007:397].) Johanna Nichols reports in her post a tentative
result from her sample: she reports that the global correlation is
present, but a division of the sample into large areas shows that the
correlation does not exist, or is even negative, in some of the areas.
On this basis, Johanna writes, "If there is really a correlation
between population size and phoneme inventory size (or anything else),
it should hold within areas as well as worldwide." She concludes
that the global phoneme-population correlation is an artifact of
population sizes in Eurasia and Africa, and areality in Africa plus
neighboring regions.<br>
<br>
Interestingly, with Dunn et al., the shoe is on the other foot with
respect to global correlations and correlations in subpopulations.
Here it is Dunn et al. who argue against the global word-order
correlations manifested in Greenbergian word order universals. Dunn et
al. argue that a correlation between various pairs of word orders are
supported in some language families but not others. Hence word-order
correlations are lineage-specific (and culture-specific) rather than
universal in the Greenbergian sense. Dunn et al. divide the global
sample into phylogenetic subpopulations rather than areal
subpopulations, but the point is the same. (There are two differences
between Dunn et al.'s analysis and the Greenberg universals: the
Greenberg universals are synchronic, while Dunn et al's data is a
sample of diachronic word order changes; and the model that Dunn et
al. tests is not the model implied by Greenbergian universals. While
these differences are important, as I argued in my post on their
paper, I believe they aren't relevant to the point being made here.)
And in the case of Dunn et al., Matthew Dryer argued in a post that
the lineage-specific correlations are random effects and the globally
identified Greenbergian word-order correlations are real.<br>
<br>
I asked a couple of physicists with whom I collaborate about what to
think of global correlations when those correlations are not found in
most or all of the subpopulations that the data may be partitioned
into (areal, phylogenetic, etc.). They both stated that a global
correlation is statistically valid even if the same correlation does
not exist in all the partitioned subpopulations. This situation may
arise when negative correlations or noncorrelations in some
subpopulations are more than compensated for by positive correlations
in other subpopulations, so that the global effect is a positive
correlation. (One of them further added that another possible reason
is that the subpopulation samples may be too small to provide a
significant correlation one way or the other.) When pressed further
about why a global correlation would not lead to the same correlations
in (large enough) subpopulations, the response was that, in the
simplest case, X is dependent not only on Y but also on a factor Z
that varies considerably from subpopulation to subpopulation; and that
one would expect the same correlations in the subpopulations if and
only if most of the observed variation in X is due to Y. In fact, this
is not the case for the phoneme-population correlation: Atkinson shows
that language family membership, which clearly varies by region,
accounts for the greatest amount of variance for phoneme inventory
size. But the other correlations still hold globally when combined
with this factor (Atkinson, supplementary materials, pp. 5-6). So it
appears that the global phoneme-population and word-order correlations
are valid, that is, there is a factor (or factors) Y that needs to be
accounted for; but there is apparently also a factor or factors Z that
lead to areal- and/or phylogeny-specific differences in the linguistic
patterns.</font></div>
<div><font face="Times New Roman" color="#000000"><br>
Of course, correlation is not causation, as we all know. We have to
find an explanatory framework that allows us to say that when X
correlates with Y (and Z), there is a causal connection between X and
Y (and Z). One problem with the global phoneme-population correlation
is that there is no satisfactory explanation for it: even the
linguists who found the correlation have only a few suggestions that
they do not consider to be strong enough to offer as an explanation.
Conversely, there is no obvious explanation why word-order
correlations might be lineage- or culture-specific. For example, no
cultural reason easily comes to mind why Proto-Indo-Europeans and
their descendants couple verb-object and adposition-noun order, but
Proto-Uto-Aztecans and their descendants do not. Nor is there an
obvious culture-specific nonlinguistic behavior that might be causally
connected to word-order patterns in the way that spatial cognition has
been shown to be connected to linguistic spatial frames of reference
by Levinson and his colleagues.<br>
<br>
Bill<br>
<br>
Hay, Jennifer and Laurie Bauer. 2007. Phoneme inventory size and
population size. Language 83.388-400.<br>
<br>
Pericliev, Vladimir. 2004. There is no correlation between the size of
a community speaking a language and the size of the phonological
inventory of that language. Linguistic Typology 8.376-83.</font></div>
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