with fairly high cognate percentages (say 60% and higher) are a reliable
There are two distinct controversies about the use of lexicostatistical
methods. One issue is whether the family trees produced for languages
with fairly high cognate percentages (say 60% and higher) are a reliable
indication of the detailed structure of "genetic" relationships
among languages. Everyone accepts that two languages with 85% cognates
are certainly related; the only question is whether they are (necessarily)
"more closely related" in a historical sense than either is
to a language whose cognate percentages with both are (say) 80%.