A Phonetically-Based Optimality Theoretic Account of Consonant ...

though labial reduction is expected only in the latter. An additional observation is that
word-initial Iml is significantly longer than word-final Im/; the same contrast in segment
duration was found in the oral consonants.
Discussion
In contrast to the oral consonants, Po data is unable to distinguish the degree of oral
constriction/reduction between intervocalic word-initial Iml (Figure 11a) and word-final Iml
(Figure 11 b); both showed no (or very slight) overall Po change, consistent across 6
speakers. Assuming the labial closure was complete in word-initial Iml (as in word-initial
Ip/), the absence of positive Po during Iml is likely due to a combination of the voicing
configuration of the glottis (i.e., less air flowing into the vocal tract) and nasal leakage. I
conclude that this lack of asymmetry between the Po data of word-initial versus word-final
Iml makes m.C2 clusters (or more generally, clusters containing a nasal coda) less
appropriate for the current investigation. I have nonetheless included NC clusters in the
data set since any instance of positive (or negative) Po during the nasal duration must
necessarily be interpreted as indicating an unreduced labial closure, and, in the case of
labial C2 clusters, temporal overlap of NC constrictions plus a reduction of N. In
interpreting Po of CC clusters, I will consider a non-zero Po as indication of unreduced
labial closure, while an absence of Po change during the duration of Iml is inconclusive
evidence for labial reduction.
Part II: Consonant clusters
Summary of attested Po patterns during CC
In addition to the notations AP, PN, PZ, and AZ, introduced in Section 4.5.1, the
following notations are used in the qualitative categorization of the Po traces in this section:
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