The genealogical classification of languages has been the subject of i
nvestigation for more than two centuries, and progress continues to be
made in deepening our understanding of language change, both in theor
etical terms and in the study of specific language families. In recent
years, as in the past, many new proposals of linguistic relationships
have been constructed, some promising to various degrees and others c
learly untenable. The debate about specific recent proposals is part o
f the healthy process needed to evaluate proposed relationships, disca
rd those that prove incorrect, and refine those of merit. Rather than
evaluating the relative linguistic ''distance'' between potentially re
lated languages, with temporal distance leading to some point where we
cannot distinguish real relationships from chance similarities, we pr
opose a scale of easy to difficult relationships in which temporal dis
tance is only one factor that makes some relationships more recognizab
le than others.