Rules for the generation of ToBI-based American English intonation1
This study presents an approach to the generation of American English intonation based on prescriptive rules that define the respective features of certain tone labels that in turn represent linguistically relevant F0 configurations. In accordance with the principles of the Tone Sequence Model the F0 contour is analyzed as a series of discrete target values that are connected by means of transitional functions. The target values are associated either with stressed syllables (pitch accents) or the margins of the phrase (phrasal tones). The targets' exact position is represented relative to pitch range and time. All tone labels are examined according to these parameters and the results are then converted into a set of rules that allows the generation of an F0 contour. Tones and Break Indices (ToBI), a system for transcribing the intonation patterns of American English, provides an inventory of tone labels and a set of example utterances available for analysis.2 Utterances from ToBI and the Boston Radio News Corpus were used for the evaluation of the generation rules: root mean squared error (RMSE) and correlation between generated and original contour were determined, and in a perception test native speakers assessed the quality of the resynthesized contours which, in general, were judged to sound natural and show few differences to the corresponding originals.
tobi american english intonation evaluation rule-based f0 generation synthesis