WK3 L5: Phonemes Part 1

• What does the acoustic signal of speech sound represent?


  Vibrations of air
• How can sounds be characterized according to their movements?

  As rapid vibrations shown in an oscillogram
• What does the y-axis of an oscillogram represent?


  The magnitude of movements
• What does the x-axis of an oscillogram represent?


  Time
• What is the relationship between movement size and sound loudness?


  Larger movements are louder
• How does frequency relate to pitch in sound?


  Higher frequency movements sound higher in pitch
• What shape does a pure tone sound have?

  A sine wave
• What is a tuning fork designed to produce?


  A sound like a pure tone
• What does a pure tone contain?


  Only a single frequency
• How is the frequency of a pure tone expressed?


  By how often the sine pattern repeats
• What is the frequency of a sound that repeats 400 times per second?


  400 Hz
• How do most speech sounds differ from pure tones?


  They are more complicated and do not look like a sine wave
• What can complex sounds be re-described as?


  Several simple vibrations (sine waves) of different frequencies added together
• What is Fourier Analysis used for?


  To pick out sine waves that add up to the waveform being analyzed
• What does a spectrogram represent?


  Sound in which frequency is the y-axis and time is the x-axis
• What is the lowest frequency in a sound called?

  Fundamental frequency (F0)
• How is the pitch we perceive in a sound linked?


  It is linked to the fundamental frequency (F0)
• What is tone in some languages related to?


  The level of F0 or the way F0 changes over time
• Does English use F0 tone?


  No, English does not use F0 tone
• What can spectrograms show when computed from real data?


  How frequencies change over time and their strength
• Why is real data considered noisy in spectrograms?

  Because it contains various unwanted sounds
• What is required to read spectrograms effectively?


  Expert training
• What are the two major categories of speech sounds?


  • Vowels: produced with unobstructed airflow
  • Consonants: produced with obstructed airflow
• How are consonants produced?


  By obstructing airflow in the vocal tract
• Why are there more possible consonants than vowels?


  Because consonants can be produced in various ways
• What are pulmonic consonants?


  Consonants produced by obstructing airflow pushed out of the lungs
• Do all languages use pulmonic consonants?


  Yes, all languages use pulmonic consonants
• What are non-pulmonic consonants?


  Consonants that involve other means of making the air move
• What are the three ways to define consonants?


  By place of articulation, manner of articulation, and voicing
• What is place of articulation?


  The location where the narrowing or obstruction occurs
• What are examples of places of articulation?

  Bilabial, dental, velar, glottal
• What does manner of articulation refer to?


  The different types of narrowing or obstruction of the vocal tract
• What are plosives?


  When the vocal tract is entirely closed, stopping airflow
• What are fricatives?


  Sounds produced from a slight gap that creates vibration
• What are approximants?


  Sounds with only a slight obstruction producing slight turbulence
• What does voicing refer to?


  The vibration of the vocal cords
• Can consonants be produced without voicing?


  Yes, consonants can be voiced or voiceless
• What is Voice Onset Time (VOT)?


  The time it takes for voicing to begin after a consonant is produced
• What is the VOT for voiced /d/ and voiceless /t/ in English?


  There are clear differences in VOT between them
• What are vowels primarily defined by?


  Vowel height, vowel backness, and roundness of the lips