Subject: Speech Processing

Topic: Speech Production, Acoustic Phonetics and Auditory Perception

Difficulty: Low

(i) ENGLISH VOWELS:

Vowels are voiced components of the sound i.e. a,e,i,o,u. The excitation is the periodic excitation generated by the fundamental frequency of the vocal cords and the sound gets modulated when it passes via the vocal tract. Speech of signals of the three vowels (a,e,i) are recorded. The welch method is used for power spectrum estimation at the signal. The sampling frequency used is 22,100 Hz and 8 bit mono recording is used.

(ii) DIPHTHONG:

It means two sounds or two tones. A diphthong is also known as a gliding vowel; meaning that there are two adjacent vowels sound occurring within the same syllable. A diphthong is a gliding monosyllabic speech item starting at or near the articulatory position for one vowel and moving towards the position of the other vowel. While pronouncing a diphthong, that is, in the case of words like eye, hay, boy, low and cow, the tongue moves and these are said to contain diphthong. In American English there are 6 diphthongs, namely |ei| in |bay|, |ai| in |buy|, |au| in |how|, |oi| in |boy| and |ju| in |you|. Diphthongs can be characterized by a time varying vocal tract area function that varies between the two vowel configurations concerned, that is, in the case of |ei| it will vary between the vowel configurations of |e| and |i|.