ThesisAuthors: Xie, Zhimin (2006)
We categorize American English phonemes into several groups: vowel, semi-vowel, nasal, whisper, fricative/affricative, closure/stop, silence and some special phonemes (/q/ and /dx/), among which five main groups (vowel, semi-vowel, nasal, fricative, stop) are further examined. Thereafter, we construct several detectors based on acoustic features for each phoneme group and compare them with HMM-based systems by testing on continuous speech data, TIMIT, and some data in unfavorable environments, like TIMIT with additive noise, and NTIMIT.
To detect vowels, a compact vowel detector based only on two acoustic features, periodicity and energy, is implemented. It performs with 86.8% accuracy and 22.4% total error rate. Even under some adverse environments, it still works stably. To detec... 
