tailieunhanh - Báo cáo khoa học: "word stress from spelling"

This paper will discuss how to determine word stress from spelling. Stress assignment is a well-established weak point for many speech synthesizers because stress dependencies cannot be determined locally. It is impossible to determine the stress of a word by looking through a five or six character window, as many speech synthesizers do. Wellknown examples such as degrade / dbgradl,tion and tMegraph / telegraph5 demonstrate that stress dependencies can span over two and three syllables. This paper will pre~nt a principled framework for dealing with these long distance dependencies. Stress assignment will be formulated in terms of Waltz' style. | Stress A 111 tai st ia Letter to Sound Relet for Speech Syetbeeit Kenneth Church AT T Bell Laboratories Abstract This paper will discuss how to determine word stress from spelling. Stress assignment is a well-established weak point for many speech synthesizers because stress dependencies cannot be determined locally. It is impossible to determine the stress of a word by looking through a five or six character window as many speech synthesizers do. Well-known examples such as degrade I degradation and telegraph telegraphy demonstrate that stress dependencies can span over two and three syllables. This paper will present a principled framework for dealing with these long distance dependencies. Stress assignment will be formulated in terms of Waltz style constraint propagation with four sources of constraints 1 syllable weight 2 part of speech 3 morphology and 4 etymology. Syllable weight is perhaps the most interesting and will be the main focus of this paper. Most of what follows has been implemented. 1. Backgrouad A speech synthesizer is a machine that inputs a text stream and outputs an accoustic signal. One small piece of this problem will be discussed here words phonemes. The resulting phonemes are then mapped into a sequence of Ipc dyads which are combined with duration and pitch information to produce speech. text intonation phrases words phonemes Ipc dyads prosody accoustics There are two general approaches to word phonemes Dictionary Lookup Letter to Sound . sound the word out from basic principles Both approaches have their advantages and disadvantages the dictionary approach fails for unknown words . proper nouns and the letter to sound approach fails when the word doesn t follow the rules which happens ail too often in English. Most speech synthesizers adopt a hybrid strategy using the dictionary when appropriate and letter to sound for the rest. Some people have suggested to me that modern speech synthesizers should do away with letter to sound .