The Methods and Purposes of Linguistic Genetic Classification
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It might seem that there is still a third method of classifying languages genetically,
namely glottochronology. When it was introduced, of course, it was intended for
another purpose, i.e., to measure the period of separation of
related languages based on
the assumption of a constant rate of change in fundamental vocabulary. In any specific
instance, the date is derived from a count of shared cognates between two languages on
the assumption of independent loss in both languages. In spite of its well-known
weaknesses, it has been up to now the only reasonably objective method we have to
accomplish this in the absence of written documentation.
However, it later began to be employed as a method of classifying languages
genetically on the assumption that there was a lower limit of chance resemblance and
that a significantly higher percentage indicated genetic relationship. Of course, viewed
in terms of its original procedures, its use for this purpose, since cognate counts were
involved, is circular. By definition there are cognates only when languages are already
related.
This method bears a superficial resemblance to multilateral comparison, since it
compares lexical forms in different languages and the
data are often set forth in
comparative tables similar to those used in the latter method, at least in its preliminary
stages. The most important difference is that it employs pairwise percentages, thereby
not taking into account the possible, multiple recurrence of resemblant forms across
many languages by which the genetic groupings become evident. A great part of the
evidence which connects related languages is in only one of the two languages
compared and, it will be argued, in some instances occurs in neither. If, for instance, we
were to compare
English and Hindi directly, the percentage of cognates would be very
low. However some of these would be recurrent over most or all of the other Indo-
European languages and hence highly diagnostic. In other instances, English would
show a cognate with, say, Slavic which was not in Hindi, while in other cases it would
be Hindi that agrees with Slavic to the exclusion of English. These independent
agreements of English and Hindi with Slavic are part of the
evidence for Indo-European
as a whole, as is, naturally, independent agreements of English and Hindi with still
other branches of Indo-European. It could even be said that agreements between Slavic
and Italic are relevant since they help to establish the overall family to which both
English and Hindi belong.
Put syllogistically, English is a Germanic language; Germanic languages are Indo-
European languages; therefore, English is an Indo-European language.
Hindi is an
Indo-Iranian language; Indo-Iranian languages are Indo-European languages; therefore,
Hindi is an Indo-European language. Hence, English and Hindi are related.
To the weakness just discussed we may add that, as languages become more
genetically distant over time, semantic changes occur so that items fall off the