Computational phonetics: empirical comparison
of prosodic
and syntax trees |
|
Dafydd Gibbon (Bielefeld) |
Empirical study of the
syntax-prosody relation is hampered by the fact that current timing models
(including rhythm models) are essentially linear, while textual structure (and
rhythm) is hierarchical. The present contribution describes a syntax-prosody
comparison heuristic based on two new algorithms: Time Tree Induction, TTI, for
building a prosodic treebank from time-annotated speech data, and Tree
Similarity Indexing, TSI, for comparing syntactic trees with the prosodic
trees. In a preliminary study, two parametrisations of the TTI algorithm, for
different tree branching conditions, are applied to sentences taken from a
read-aloud narrative, and compared with parses of the same sentences, using the
TSI. In addition, null-hypotheses in the form of flat bracketing of the
sentences are compared. A preference for iambic (heavy rightmost branch)
grouping in English, and considerably less clear preferences for a tone
language (Ibibio, Lower Cross, Nigeria) are found. The resulting quantitative
evidence for syntax-prosody relations has potential applications in speech
genre characterisation and in duration models for speech synthesis.