246 Speech Production and Perception
words in heterogeneous sets, because segments in the over-
lapping syllables would remain prepared for production.
Meyer found shorter response latencies only in the homoge-
neous sets in which the first syllable was shared across re-
sponse words. In a follow-up study, Meyer (1991) showed
savings when word onsets were shared but not when rimes
were shared. On the one hand, these studies provide evidence
converging with that of Meyer and Shriefers (1991) for form
priming and left-to-right preparation. However, the evidence
appears to conflict in that Meyer (1990, 1991) found no end-
overlap priming, whereas Meyer and Shriefers did. Levelt
et al. (1999) suggested, as a resolution, that the latter results
occur as the segments of a lexical item are activated, whereas
the results of Meyer reflect prosodification (that is, merging
of those segments with the metrical frame).
The theory of Levelt et al. (1999) makes a variety of
predictions about the prosodification process. First, the
phonological segments and the metrical frame are retrieved
as separate entities. Second, the metrical frame specifies only
the number of syllables in the word and the word’s stress pat-
tern; it does not specify the CV pattern of the syllables. Third,
for words with the default stress pattern, no metrical frame is
retrieved; rather, it is computed online.
Roelofs and Meyer (1998) tested these predictions using
the implicit priming procedure. In the first experiment, in
homogeneous sets, response words were disyllables with
second-syllable stress that shared their first syllables; het-
erogeneous sets had unrelated first syllables. Alternatively,
homogeneous (same first syllables) and heterogeneous
(unrelated first syllables) response words had a variable num-
ber of syllables (2–4) with second-syllable stress. None of the
words in this and the following experiments had the default
stress pattern, so that, according to the theory, a metrical
frame had to be retrieved. Priming (that is, an advantage in
response latency for the homogeneous as compared to the
heterogeneous sets) occurred only if the number of syllables
was the same across response words. This is consistent with
the prediction that the metrical frame specifies the number of
syllables. A second experiment confirmed that, with the num-
ber of syllables per response word held constant, the stress
pattern had to be shared for priming to occur. A third experi-
ment tested the prediction that shared CV structure did not in-
crease priming. In this experiment, response words were
monosyllables that, in homogeneous sets, shared their initial
consonant clusters (e.g., br). In one kind of homogeneous set,
the words shared their CV structure (e.g., all were CCVCs);
in another kind of homogeneous set, they had different CV
structures. The two homogeneous sets produced equivalent
priming relative to latencies to produce heterogeneous re-
sponses. This is consistent with the claim of the theory that
the metrical frame only specifies the number of syllables, but
not the CV structure of each syllable. Subsequent experi-
ments showed that shared number of syllables with no seg-
mental overlap and shared stress pattern without segmental
overlap give rise to no priming. Accordingly, it is the integra-
tion of the word’s phonological segments with the metrical
frame that underlies the priming effect.
Finally, in a study by Meyer, Roelofs, and Schiller, de-
scribed by Levelt et al. (1999), Meyer et al. examined words
with the default stress pattern for Dutch. In this case, no met-
rical frame should be retrieved and so none can be shared
across response words. Meyer et al. found that for words that
shared their initial CVs and that had the default stress pattern
for Dutch, shared metrical structure did not increase priming.
The next process in the theory is phonetic encoding in
which talkers establish a gestural score (see section titled
“Feature Systems”) for each phonological word. This phase
of talking is not well worked out by Levelt et al. (1999), and
it is the topic of the next major section (“Speech Produc-
tion”). Accordingly, I will not consider it further here.Disagreements Between the Theories of Dell, 1986,
and Levelt et al., 1999Two salient differences between the theory of Dell (1986),
developed largely from speech error data, and that of Levelt
et al. (1999), developed largely from speeded naming data,
concern feedback and syllabification. Dell’s model includes
feedback. The theory of Levelt et al. and Roelof and Meyer’s
(1998) model WEAVER do not. In Dell’s model, phones are
slotted into a syllable frame, whereas in the theory of Levelt
et al., they are slotted into a metrical frame that specifies the
number of syllables, but not their internal structure.
As for the disagreement about feedback, the crucial error
data supporting feedback consist of such errors as saying
winterforsummer,in which the target and the error word
share both form and meaning. In Dell’s (1986) model, form
can affect activation of lexical items via feedback links in the
network. Levelt et al. (1999) suggest that these errors are
monitoring failures. Speakers monitor their speech, and they
often correct their errors. Levelt et al. suggest that the more
phonologically similar the target and error words are, the
more likely the monitor is to fail to detect the error.
The second disagreement is about when during planning
phonological segments are syllabified. In Dell’s (1986)
model, phones are identified with syllable positions in the
lexicon, and they are slotted into abstract syllable frames in
the course of planning for production. In the theory of Levelt
et al. (1999), syllabification is a late process, as it has to be to
allow resyllabification to occur. There is evidence favoring