UCL Division of Psychology and Language Sciences

Overview

• Stationary vs Dynamic Sounds Acoustics of Speech • Diphthongs and Hearing • Approximants • Acoustic consequences of obstructions Lecture 2-5 – Formant transitions Formant Transitions • Manner Series

Stationary vs. Dynamic Stationary vs. Dynamic

• Stationary sounds • Dynamic sounds – e.g. monophthongs and fricatives – e.g. diphthongs, approximants, affricates, plosives – explain production using source-filter model – dynamic changes to filter as vocal tract changes – stationary source, stationary filter configuration – study with spectral cross-sections: – dynamic changes to source if voicing starts/stops or • formant frequencies if turbulence arises • spectral peaks & bandwidths – study with spectrographic analysis: • formant movements

Diphthongs Approximants

• Smooth movements of tongue, jaw, lips • [w] and [j] • Causes smooth changes in resonant properties of – have ‘target’ configurations that are vowel-like supra-laryngeal vocal tract – sometimes considered as ‘half’ vowels • Seen as smooth formant movements

SPSC2003 Acoustics of Speech and Hearing 1 UCL Division of Psychology and Language Sciences

Approximants Approximants

• [l] • [r] – non-vowel-like – non-vowel-like configuration, but still see configuration, but still clear formant pattern see clear formant pattern – exact quality affected by – retroflexion of tongue position of back of tongue causes considerable – allophonic variants lowering of F3 according to syllable position in English RP

Approximants Manner Series 1

• Generally – Differ from vowels in that articulations are more Sequence extreme of vowels: Z@ h9 @\ – Differ from diphthongs in that transitions are more rapid

Approximant: Z@ i @\

Obstruction in Vocal Tract Spectrographic pattern

• Open • Study changes in spectrographic pattern as obstruction – tube has clear resonances, excited by sound occurs generated at larynx • Obstructed – only cavity in front of obstruction available to shape sound – any sound generated at larynx can’t get out – lack of air-flow eventually stops vocal fold vibration

SPSC2003 Acoustics of Speech and Hearing 2 UCL Division of Psychology and Language Sciences

Spectrographic Pattern Transitions into Obstruction

• Stylised spectrogram • F1 transition is usually towards low-frequencies • Formant F frequencies shift – an indicator that an obstruction is occurring as vocal tract changes shape – a cue to help identify the manner of the consonant • From vowel target towards F2 consonantal target • Energy falls as obstruction F1 increases t vowel transition stop-gap burst Approximant Nasal Plosive

Transitions into Obstruction Transitions from Obstructions

• F2 transition is towards different frequencies • Mirror image of pattern of transitions into depending on place of obstruction obstruction – an indicator where the obstruction is occurring – F1 moves from low frequency into vowel – a cue to help identify the place of the consonant – F2 moves from position determined by place of consonant into vowel

Bilabial Alveolar Velar Bilabial Alveolar Velar

Transitions form patterns Locus Frequency

• The exact shape of a transition depends on – manner of consonant – place of consonant – formant frequencies of adjoining vowel • Exact frequencies present in transition not as useful to listener as direction of transition • These directions are called locus frequencies

SPSC2003 Acoustics of Speech and Hearing 3 UCL Division of Psychology and Language Sciences

Locus Frequency Consonant Manner

vowel stop • Consonant manner forms a series F F2 for [i] least degree, slowest Diphthong F2 for [e] F2 locus Approximant

F2 for [a] Fricative Stop Transition shape depends on vowel greatest degree, fastest but ‘target’ or locus frequency constant • Similar patterning seen in formant transitions t for different manners of articulation at same place

Manner Series 1 Manner Series 2

Voiceless Sequence Fricative of vowels: [@ B @] Z@ h9 @\

Approximant: Voiceless Z@ i @\ Plosive [@ b @ ]

Summary Lab Experiment

• Dynamic sounds caused by changing vocal tract • Your recordings of • Changing vocal tract causes formant movements .2!a2. .2!v2. .2!l2. or ‘transitions’ .2!u2. .2!o2. .2!e2. • Formant transition shape depends on vowel and .!?T?. consonant • Study change in spectrographic pattern with • Characteristics of formant transitions give change in manner ‘cues’ to consonant place and manner • Build a poster of a “key” for identifying these sounds from their spectrogram

SPSC2003 Acoustics of Speech and Hearing 4