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word boundary- hypothesisation in hindi speech - Speech and ...

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2. Lexical match was performed at each syllable, which means that a <strong>word</strong> <strong>boundary</strong><br />

was assumed after every syllable.<br />

3. Lexical match was <strong>in</strong>itiated at the beg<strong>in</strong>n<strong>in</strong>g of the sentence <strong>and</strong> subsequently at the<br />

conclusion of each successful lexical match. This strategy was used <strong>in</strong> most <strong>speech</strong><br />

recognition systems [Cole <strong>and</strong> Jakimik 19801.<br />

4. Lexical match was <strong>in</strong>itiated at each strong syllable. This strategy was based on the<br />

Metrical. Segmentation Strategy(MSS) suggested for English [Cutler <strong>and</strong> Carter 19871.<br />

Thus, <strong>in</strong> this strategy, <strong>in</strong>formation regard<strong>in</strong>g <strong>word</strong> boundaries was used <strong>in</strong> match<strong>in</strong>g.<br />

The above four lexical match strategies were compared on three types of <strong>in</strong>put<br />

representation of <strong>in</strong>creas<strong>in</strong>g complexity, namely, (a) A sentence represented as a<br />

sequence of phonemes, (b) a sentence transcribed such that the strong syllables were<br />

transcribed exactly whereas the weak syllables were transcribed <strong>in</strong>to their broadclass<br />

categories, <strong>and</strong> (c) a sentence transcribed such that the strong syllables were<br />

transcribed <strong>in</strong>to their midclass categories <strong>and</strong> the weak syllables <strong>in</strong>to their broadclass<br />

categories. Thus the above three types of <strong>in</strong>puts were of <strong>in</strong>creas<strong>in</strong>g complexity. The<br />

results of the study were as follows:<br />

1. For <strong>in</strong>put type (a), Strategies 1 <strong>and</strong> 2 produced more match<strong>in</strong>g <strong>word</strong> sequences than<br />

strategies 3 <strong>and</strong> 4, as expected.<br />

2. For <strong>in</strong>put types (b) <strong>and</strong> (c), strategy 1 aga<strong>in</strong> produced the highest number of<br />

match<strong>in</strong>g <strong>word</strong> sequences. But unlike the earlier case, strategy 2 performed better than<br />

strategy 3 <strong>in</strong> that it produced less number of match<strong>in</strong>g <strong>word</strong> sequences. Strategy 4<br />

performed best by produc<strong>in</strong>g the least number of match<strong>in</strong>g <strong>word</strong> sequences.<br />

The above results established that knowledge of the <strong>word</strong> boundaries (even if it<br />

is only partial as <strong>in</strong> strategy 2) can improve the performance of the lexical match,<br />

especially when the <strong>in</strong>put is only partially known (midclass or broadclass str<strong>in</strong>gs). Of

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