Definition of Phonetics

Phonetics is the branch of linguistics that studies the physical sounds of human speech. It examines how speech sounds are produced, transmitted, and perceived. Unlike phonology, which deals with the abstract and functional aspects of sounds, phonetics focuses on their physical and articulatory properties. Phonetics is essential in understanding pronunciation, language learning, and speech recognition technologies.

Branches of Phonetics

Phonetics is divided into three main branches:

1. Articulatory Phonetics

This branch studies how speech sounds are produced by the human vocal tract. It focuses on the movement of the tongue, lips, vocal cords, and other speech organs.

Example:

  • The sound /p/ in pat is produced by closing the lips and releasing air suddenly (a bilabial plosive).
  • The sound /s/ in sip is produced by placing the tongue near the alveolar ridge and allowing air to pass through (an alveolar fricative).

2. Acoustic Phonetics

This branch deals with the physical properties of speech sounds, such as frequency, amplitude, and duration. It studies how sounds travel as sound waves through the air.

Example:

  • The difference between /s/ and /ʃ/ (as in ship) can be measured in terms of frequency. /ʃ/ has a lower frequency than /s/.
  • A spectrogram is used to visually analyze sound waves and their frequencies.

3. Auditory Phonetics

This branch examines how speech sounds are perceived by the human ear and processed by the brain. It studies how listeners distinguish between different sounds.

Example:

  • Native speakers of English can easily differentiate between /r/ and /l/, but Japanese speakers may struggle because their language does not make this distinction.
  • When hearing a whispered sentence, listeners rely on contextual clues to identify missing sounds.

Speech Organs and Their Role in Sound Production

The production of speech sounds involves different speech organs, which are classified as follows:

1. Respiratory System (Lungs, Trachea, and Diaphragm)

  • Provides airflow for speech production.
  • Air is pushed from the lungs through the trachea to create sound.
  • Without airflow, speech would not be possible.

2. Phonatory System (Larynx and Vocal Cords)

  • The larynx (voice box) houses the vocal cords (vocal folds), which vibrate to produce sound.
  • Sounds can be voiced (vocal cords vibrate) or voiceless (no vibration).

Examples:

  • Voiced Sounds: /b/, /d/, /g/, /z/
  • Voiceless Sounds: /p/, /t/, /k/, /s/

3. Articulatory System (Oral and Nasal Cavities)

This system shapes the airflow into different sounds using the following organs:

Articulator Function Example Sounds
Lips Used to produce bilabial sounds /p/, /b/, /m/
Teeth Used in dental sounds /θ/ (thin), /ð/ (this)
Alveolar Ridge Located behind the upper teeth, important for alveolar sounds /t/, /d/, /s/, /z/, /n/
Palate (Hard Palate) The roof of the mouth, important for palatal sounds /ʃ/ (ship), /ʒ/ (measure)
Velum (Soft Palate) Controls nasal vs. oral airflow /k/, /g/, /ŋ/ (sing)
Tongue The most flexible speech organ, used in various places of articulation /l/, /r/, /j/ (yes)
Glottis Opening between the vocal cords, used for glottal sounds /h/, /ʔ/ (uh-oh)

Classification of Speech Sounds

Speech sounds in English are categorized into consonants and vowels.

1. Consonants

Consonants are sounds produced with some degree of obstruction in the vocal tract. They are classified based on three criteria:

A. Manner of Articulation (How the sound is produced)

Examples:

  • Plosives (Stops): Complete blockage of airflow followed by a release. (p, b, t, d, k, g)
  • Fricatives: Airflow is partially blocked, creating friction. (f, v, s, z, ʃ, ʒ, θ, ð, h)
  • Affricates: Combination of a stop and a fricative. (ʧ as in church, ʤ as in judge)
  • Nasals: Air flows through the nose. (m, n, ŋ as in sing)
  • Liquids: Air flows smoothly around the tongue. (l, r)
  • Glides (Semivowels): Slight closure of articulators, like vowels. (w, j as in yes).

B. Place of Articulation (Where the sound is produced)

Examples:

  • Bilabial: Both lips (p, b, m, w)
  • Labiodental: Lower lip and upper teeth (f, v)
  • Dental: Tongue and upper teeth (θ, ð)
  • Alveolar: Tongue and alveolar ridge (t, d, s, z, n, l)
  • Palatal: Tongue and hard palate (ʃ, ʒ, ʧ, ʤ, j)
  • Velar: Tongue and soft palate (k, g, ŋ)
  • Glottal: Sound produced in the glottis (h, ʔ)

C. Voicing (Whether vocal cords vibrate or not)

Examples:

  • Voiced Sounds: /b/, /d/, /g/, /v/, /z/
  • Voiceless Sounds: /p/, /t/, /k/, /f/, /s/

2. Vowels

Vowels are sounds produced without significant obstruction of airflow. They are classified based on:

A. Tongue Height (High, Mid, Low)

Examples:

  • High: /i:/ (see), /u:/ (food)
  • Mid: /e/ (bed), /o/ (hot)
  • Low: /æ/ (cat), /ɑ:/ (car)

B. Tongue Position (Front, Central, Back)

Examples:

  • Front: /i:/ (seat), /æ/ (cat)
  • Central: /ə/ (sofa), /ʌ/ (cup)
  • Back: /u:/ (food), /ɔ:/ (law)

C. Lip Rounding (Rounded, Unrounded)

Examples:

  • Rounded: /u:/ (boot), /ɔ:/ (thought)
  • Unrounded: /i:/ (meet), /æ/ (cat)

D. Tenseness (Tense vs. Lax)

Examples:

  • Tense: /i:/ (feet), /u:/ (food)
  • Lax: /ɪ/ (bit), /ʊ/ (foot)

Phonetics is the study of speech sounds from production to perception. It plays a crucial role in language learning, speech therapy, and linguistic research. Understanding phonetics helps improve pronunciation, recognize accents, and analyze sound patterns across languages.