Lexical stress and lexical discriminability: Stressed syllables are more informative, but why?

Recent studies have suggested that recognition systems should concentrate their efforts on the identification of stressed syllables, as they contain disproportionately more information than do unstressed syllables. The paper investigates whether this increased informativeness may be outweighed by the informational disadvantage associated with transcribing consecutive segments within the same syllable. Phonotactic correlations between such adjacent segments suggest that the most informative transcription of a polysyllabic word may be one where reliable phonemic information is scattered across different syllables. Lexical statistics are presented which support this view. In addition, the paper considers the reasons for the increased informativeness of stressed syllables, and shows that this is because lexical stress preserves vowel distinctions (and hence information) which would otherwise be lost in lexically unstressed syllables.