Phonetics and Acoustics

Speech sound science is the study of

• Physiological and physical aspects of speech

• Perception

Speech perception is

• Understandings of spoken speech

• How a listener responds to speech

What are the two branches of speech science

• Phonetics

• Acoustics

Phonetics

Study of speech sound production and perception

• Articulation

Acoustics

Study of physical aspects of speech production produced by the articulators

Language (linguistic definition)

System of symbols used to express concepts formed through exposure/experience

Language (Behavior definition)

Verbal behaviors shaped and maintained by social communities

Phonology

Scientific study of sound systems and patterns used to create sounds/words

Phonemes

Smallest units of sounds that can affect meaning

Allophones

Variations of phonemes that do not change word meanings

The International Phonetic Alphabet is a set of ____ symbols that represent spoken sounds

Orthographic

Broad transcription

The sound of speech sound production and perception

• Phonetic transcription = transcribing allophones enclosed in brackets [ ]

• Phonemic transcription = refers to transcribing words/sounds based on idealized phonemes enclosed in / /

Narrow transcription

Provides additional details on how a speaker produces a sound including atypical sound production

• Diacritic marks are used to represent variation

Speech sounds can be divided into two categories

• Consonants

• Vowels

Consonant and vowels can be described by

• Place

• Manner

• Voicing

Consonants

Produced by articulatory movements that modify the airstream in some manner

Vowels

Produced with an open vocal tract with no points of constriction

Consonants and vowels work together to produce syllables which are the motor unit phonetic unit composed of 3 parts

• Onset

• Nucleus

• Coda

Onset

The initial consonant or consonant cluster of a syllable

Nucleus

The vowel or dipthong in the middle of the syllable

Coda

Consonant at the end of the syllable

Open syllables end in

Vowels

• my, key, ski

Closed syllables end in

Consonants

• cook, lip, hiss

Speech sound production is a ____ process where context sounds are produced in will influence production of other sounds with the same context

Dynamic

Suprasegmentals

Features of prosody that add meaning and variety to speech

Suprasegmentals include (6)

• length

• Stress

• Rate

• Pitch

• Volume

• Juncture

Length

How long the phoneme is produced for

• some vowels may have short or long consonants

Stress

Can change the meaning of words

• stressed syllables are called primary stress

• Unstressed syllables are called secondary stress or weak syllables

Rate

The speed of speech

Pitch

Frequency in which a phoneme is produced. Rising and falling tones differentiates between statements and questions

Volume/Intensity

How loud a phoneme is produced

Juncture

Aka vocal punctuation

• Pauses during speech that denote grammar/word differences

• Ice cream vs I scream

Acoustics

The study of physical properties of sound and how sound is generated and propagated

Sound is a result of ____ in a medium, such as air, gas, or liquid

Vibrations

Psychoacoustics

Study of how humans respond to sound

Soundwaves are movements of particles in a medium containing

• expansion

• contraction

Compression

A phase in sound production where displaced molecules move closer together

Rarefaction

• Opposite of compression

• Molecules move apart and return to equilibrium

The number of cycles per second is called

• Hz

• Frequency of vibration

Pure tones

Tones that include only a single frequency

Complex tones

Tones that have two or more pure tones of differing frequencies

What determines frequency?

Mass and stiffness

Natural Frequency

Frequency in which a sound source normally vibrates

Fundamental frequency

The lowest frequency of a periodic wave

Amplitude

Magnitude and direction of particle displacement during vibration

Intensity

• Sound pressure

• The amount of energy transmitted per second over an area

Density

Amount of mass per unit volume

• Affects how well a sound is transmitted

• Higher density = faster travel

Reflection

Phenomenon of sound waves traveling back after hitting an obstacle

Refraction

Bending of sound waves due to change in speed

Resonance

Modification of sound by other sources

• Change of tone when sound passes through the nasal cavity

Sound spectrogran

An instrument used for speech sound analysis that represents sound graphically using

• Spectrogram

• Spectrum

Spectrogram

Graphic display of acoustic features of speech sounds

Spectrum

Patterns of physical energy across a frequency range that is released when sound is produced

On a spectrogram how are formants displated

• They are resonances of the vocal tract

• They are bands of energy represented by darker areas

Cavity features

Refer to the movement of the articulators and how it changes shape of the vocal cavity

• Alters formant frequency

Formant transition

Rapid changes in the formant frequency as speech sound productions transitions from one sound to the next

Fundamental frequency

Lowest frequency of a periodic wave with the greatest wavelength

The ___ and ___ affect fundamental frequency the most

• Shape

• Length

Vocal onset time

The time between release of a consonant and begining of vowel

Voice termination time

Time it takes to stop vocal activity

Sound pressure level

• dB SPL

• Intensity of sound is expressed by using decibels at a certain sound pressure

Humans can only hear frequencies between

20-20,000Hz

Intensity of conversational speech varies between

50 to 70 dB SPL

Hearing level

Sounds need to reach a minimum intensity to be heard by humans