The best evidence of the obsolescence of any word is that it should
still be frequently heard in some proverb or phrase, but never out
of it. The homophonic condition is like that of _aural_ and _oral_,
of which it is impossible to make practical use.[14] We speak of an
_aural surgeon_ and of _oral teaching_, but out of such combinations
the words have no sense. It happens that oral teaching must be aural
on the pupil's side, but that only adds to the confusion.

[Footnote 14: The words _aural_ and _oral_ are distinguished in
the pronunciation of the North Midlands and in Scotland, and the
difference between the first syllables is shown in the Oxford
dictionary. In Southern English no trace of differentiation remains.]

In deciding whether any obsolete homophone has been lost by its
homophony, I should make much of the consideration whether the word
had supplied a real need, by naming a conception that no other word
so fitly represented; hence its survival in a proverb is of special
value, because the words of proverbs are both apt and popular; so that
for the disuse of such a word there would seem to be no other cause so
likely and sufficient as damage to its signification.

The glossary is relied on to contain, besides its other items, all
the obsolete words: the homophones separated out from these will show
various grades of obsolescence, and very different values as examples
bearing on the question at issue.

_Table of homophones taken from among the obsolete words in Cunliffe's
'A New Shakespearean Dictionary,' Blackie_, 1910.]