cognate vocab as a measure of relatedness

[David Mead]

In response to Adrian's inquiry,

>3) Is there a commonly accepted percentage of cognate basic vocabulary, at
>or below which one might expect two varieties to be considered distinct
>languages, rather than dialects of the same language?

Below 60% lexical similarity, two isolects can be considered different
languages.  Above 90%, in most cases it is safe to assume that two isolects
are the same language.  Between 60% and 90% is a grey area, where
lexicostatistics is simply too blunt of an instrument to tell you anything
reliable about intelligibility.  It is probably best to think of
intelligibility in terms of "cost" or "effort", high intelligibility
implying little effort on the part of interlocutors, lower intelligibility
implying higher effort.

>4) Can you recommend a reference discussing this kind of approach?

My information from:

Joseph E. Grimes. 1985. Correlations between vocabulary similarity and
intelligibility. Notes on Linguistics 41:19-33. Dallas: SIL.

Joseph E. Grimes. 1995. Language survey reference guide. Dallas: SIL.

Richard Loving, ed. 1977. Language variation and survey techniques.
(Workpapers in Papua New Guinea Languages, 21.) Ukarumpa: SIL.



>Thanks,
>Adrian Clynes
>
>