The contrastive hierarchy in phonology 2009 Dresher.pdf - CUNY ...

(8.20) Similarity measures (S = shared classes, U = unshared classes)
Pair S U S/S+U Pair S U S/S+U
a. /u, o/ 3 4 0.43 b. /i, e/ 2 4 0.33
c. /o, a/ 2 4 0.33 d. /u, a/ 2 4 0.33
e. /e, o/ 2 5 0.29 f. /i, u/ 2 5 0.29
g. /i, a/ 1 5 0.17 h. /e, a/ 1 5 0.17
i. /i, o/ 1 7 0.13 j. /u, e/ 1 7 0.13
The classes [syllabic, round, back] and [syllabic, back] are distinct because /a/ is
a member of the latter, but not the former. In the case of unshared classes, the
features [round] and [back] function together, because /a/ is neither [high] nor
[open], in this system of features, so [syllabic, high/open, round, back] =
[syllabic, high/open, round] = [syllabic, high/open, back].
The features [back] and [round] do similar contrastive work in most
classes; therefore, the weight they are accorded by the similarity measures is
reduced, somewhat capturing the notion that these features make each other
logically redundant in most cases, without actually designating one as
contrastive and the other as redundant. Though their weight is reduced, they are
not entirely disregarded: thus, /u, o/ are computed to be more similar to each
other than /i, e/.
This procedure is very sensitive to the choice of features: different choices
of features can change the results quite substantially. If we had a feature [non-
round], for example, the front and back vowels would appear to be more
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