Title of the article

4.3.Syllabic structure

Phonotactic constraints might hint at how the stream of phonemes is organized in the language processing system. The popular phoneme, syllable and word entities may not be the only units that we use for lexical access and production. There are suggestions that in addition, some sub-syllabic elements are involved in those processes, that is, the syllables might have not linear structure, but more complex representations (Kessler & Treiman, 1997). For that purpose, we will analyze how the phoneme prediction error at a threshold of 0.016 - where the network resulted in best word recognition - is located within words with respect to the following sub-syllabic elements - onset, nucleus and coda. The particular hypothesis that will be tested is whether Dutch monosyllables follow the structure below that was found in English as well (Kessler & Treiman, 1997).
( Onset - Rhyme (Nucleus - Coda) )
The distribution of phoneme error within words (Table 4a) shows that the network makes more mistakes at the beginning than at the end of words, where SRN becomes more confident in its decision. This could be explained with increasing contextual information that more severely restricts possible phonemic combinations. A more precise analysis of the error position in the onset, the nucleus and the coda further reveals other interesting phenomena (Table 4b).

Table 4. Distribution of phoneme prediction error at a threshold of 0.016 by (a) phoneme position within words and (b) phoneme position within sub-syllables. Word and Onset positions start from 2, because the prediction starts after the first phoneme.

1. 
   
   

Word Position	2	3	4	5	6	7	8
Error (%)	4.3	1.7	1.4	0.6	0.3	0.3	0.00

2. 
   
   

Sub-syllabes	Onset		Nucleus	Coda
Relative Position	2 2.6	3 0.0	1 4.5	1 1.0	2 1.5	3 2.0	4 2.6
Error (%)

First, error within the coda increases at the coda's end. We attribute this to error accumulated toward the end of the words, as was predicted earlier. The mean entropy in the coda (1.32; σ = 0.87) is smaller than the mean entropy in the onset (1.53; σ = 0.78), where we do not observe such effects. So looser constraints are not the reason for the relatively greater error in the coda. Next, the error at the transition onset-nucleus is much higher than the error at the surrounding positions, which means that the break between onset and rhyme (the conjunction nucleus-coda) is significant. This distribution is also consistent with the statistical finding that the entropy is larger in the body (the transition point onset-nucleus) (3.45; σ = 0.39), than in the rhyme (1.94; σ = 1.21). All this data support the hypothesis that onset and rhyme play significant roles in lexical access and that the syllabic structure confirmed for English by Kessler & Treiman (1997) is valid for Dutch, too.