Frequency, Pitch, Tone and Length

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# Frequency, Pitch, Tone and Length - PowerPoint PPT Presentation

Frequency, Pitch, Tone and Length. October 15, 2012 Thanks to Chilin Shih for making some of these lecture materials available. Announcements. For Wednesday: transcription exercise on tone. Yoruba and Cantonese For Friday: mid-sagittal diagram exercise

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Frequency, Pitch, Tone and Length

October 15, 2012

Thanks to Chilin Shih for making some of these lecture materials available.

Announcements
• For Wednesday: transcription exercise on tone.
• Yoruba and Cantonese
• For Friday: mid-sagittal diagram exercise
• Check it out on the course web page.
• Production exercise #2 due at 5 pm next Monday (the 22nd).
• Okay, let’s put together some complex waves…
Sine Waves
• The reading on the pressure level meter will fluctuate between high and low pressure values
• In the simplest case, the variations in pressure level will look like a sine wave.

pressure

time

Other Basic Sinewave concepts
• Sinewaves are periodic; i.e., they recur over time.
• The period is the amount of time it takes for the pattern to repeat itself.
• The frequency is the number of times, within a given timeframe, that the pattern repeats itself.
• Frequency = 1 / period
• usually measured in cycles per second, or Hertz
• The peakamplitude is the the maximum amount of vertical displacement in the wave
• = maximum/minimum amount of pressure
Complex Waves
• When more than one sinewave gets combined, they form a complex wave.
• At any given time, each wave will have some amplitude value.
• A1(t1) := Amplitude value of sinewave 1 at time 1
• A2(t1) := Amplitude value of sinewave 2 at time 1
• The amplitude value of the complex wave is the sum of these values.
• Ac(t1) = A1 (t1) + A2 (t1)
Complex Wave Example
• Take waveform 1:
• high amplitude
• low frequency

+

• low amplitude
• high frequency

=

• The sum is this complex waveform:
Other Examples
• 480 Hz tone
• 620 Hz tone
• the combo = ?
Fundamental Frequency
• The fundamental frequency of a complex wave is the frequency at which the complex wave repeats itself.
• = greatest common denominator of frequencies of component waves.
• Greatest common denominator =
• largest number that two (or more) numbers can be divided by to yield an integer (whole number) value.
• Q: What’s the fundamental frequency of a complex wave consisting of 600 Hz and 800 Hz tones?
• How about one with 120 Hz and 150 Hz tones?
Linguistically Speaking
• In speech, the fundamental frequency of voiced sounds is based on the rate at which the vocal folds open and close.
• The wave set up by the vocal folds is a complex wave.
Complex Wave Visual
• Combination of 100 Hz and 300 Hz wave.
• Voicing sort of looks like this, but it’s even more complex:
Why Should You Care?
• The modulation of fundamental frequency in speech can have linguistic meaning.
• Tone
• Pitch Accent
• Stress
• Intonation
• Since this modulation can occur (relatively) independently of the stream of vowel and consonant segments in speech…
• these linguistic properties are often referred to as suprasegmentals.
Suprasegmentals
• Suprasegmentals are phonetic features of speech which are “above the segment”
• Tone/Accent/Intonation
• Quantity
• Stress
• “Suprasegmental features are established by a comparison of items in a sequence.” --Ilse Lehiste (1970)
•  Suprasegmental features are always defined in a relative manner.
Where Tone Comes From

Here’s a waveform for my vowel :

• The acoustic shockwave of each opening of the vocal folds shows up as a vertical bar in the waveform.
• A “voicing bar”
Voicing Bar Close-up

Individual glottal pulses

Voicing bars, really close up
• Voicing is a complex wave. (i.e., not sinusoidal)
• The fundamental frequency of voicing can be calculated by measuring the period between glottal pulses.
Voicing bars, really close up

period

• Frequency = 1 / period
• In this case, period = .008 seconds, so frequency = ?
Pitch Tracks
• Measuring the fundamental frequency (F0) at every step in a sound file yields a pitch track.
• Time on the x-axis.
• Fundamental frequency on the y-axis.

F0

time

I’d like to collect sea shells this after noon

Just So You Know
• Praat has an automatic pitch tracker.
• Check it out.
• It can be messed up by:
• voiceless sounds
• obstruents (stops, fricatives, affricates)
• Also, it can sometimes double or halve the correct fundamental frequency.
• I’ll spare you the technical reasons why.
• In general, though, it works well.
Tone
• Tone is the linguistic use of fundamental frequency to signal important differences in meaning.
• Note:
• Acoustic = Fundamental Frequency
• Perceptual = Pitch
• Linguistic = Tone
• English is a tone language…
• Sort of. For one set of words only.
A Typology
• F0 generally varies in three different ways in language:

1. Tone languages (Chinese, Navajo, Igbo)

• Lexically determined tone on every syllable or word

2. Accentual languages (Japanese, Swedish)

• The location of an accent in a particular word is lexically marked.

3. Stress languages (English, Russian)

• It’s complicated.
Mandarin Tone
• Mandarin (Chinese) is a classic example of a tone language.

ma1: mother

ma2: hemp

ma3: horse

ma4: to scold

Mandarin Sentences

ma1-ma0 ma4 ma3.

“Mother scolds the horse.”

ma3 ma4 ma1-ma0.

“The horse scolds mother.”

How to Transcribe Tone
• Tones are defined by the pattern they make through a speaker’s frequency range.
• The frequency range is usually assumed to encompass five levels (1-5).
• (although this can vary, depending on the language)

Highest F0

5

4

3

2

Lowest F0

1

Tone

1

2

3

4

• In Mandarin, tones span a frequency range of 1-5
• Each tone is denoted by its (numerical) path through the frequency range
• Each syllable can also be labeled with a tone number (e.g., ma1, ma2, ma3, ma4)
How to Transcribe Tone
• Tone is relative
• i.e., not absolute
• Each speaker has a unique frequency range. For example:

Male

Female

~200 Hz

Highest F0

5

~350 Hz

4

3

2

~100 Hz

Lowest F0

~150 Hz

1

Relativity, in Reality
• The same tones may be denoted by completely different frequencies, depending on the speaker.
• Tone is an abstract linguistic unit.

female speaker

ma, tone 1 (55)

male speaker

How To Transcribe Tone

female speaker

ma, tone 4 (51)

male speaker

Some speakers also use more of their frequency range.

Even More Tones

level tones

contour tones

Variations
• Other tone languages only have two or three tone targets
• These are transcribed as sequences of High (H) and Low (L) tones. (or also Mid (M) tones)
• They can also be labeled with accents over vowels
• High = ´
• Low = `
• In these languages, tone can be used for grammatical markers (tense, possession)
Ibibio Tones
• Ibibio is spoken in southern Nigeria
Accentual Languages
• In accentual languages, there is only one pitch accent associated with each word.
• The pitch accent is realized on only one syllable in the word.
• The other syllables in the word can have no accent.
• Accent is lexically determined, so there can be minimal pairs.
• Japanese is a pitch accent language…
• for some, but not all, words
• for some, but not all, dialects
Japanese
• Japanese words have one High accent
• it attaches to one “mora” in the word
• A mora = a vowel, or a consonant following a vowel, within a syllable.
• For example:
• [ni] ‘two’ has one mora.
• [san] ‘three’ has two morae.
• The first mora, if not accented, has a Low F0.
• Morae following the accent have Low F0.

It’s actually slightly more complicated than this; for more info, see: http://sp.cis.iwate-u.ac.jp/sp/lesson/j/doc/accent.html

Japanese Examples
• asa ‘morning’ H-L
• asa ‘hemp’ L-H

“chopsticks” H-L-L

• “bridge” L-H-L
• “edge” L-H-H
Length Distinctions
• Another suprasegmental linguistic feature is quantity.
• Note:
• Quantity = Linguistic
• Length = Perceptual
• Duration = Acoustic
• Quantity distinctions are also relative.
• depend on speaker
• depend on speaking rate

= 150 milliseconds

= 275 milliseconds

• Differences in quantity between segments translates to relative differences in duration.
Italian
• Italian contrasts both long and short vowels and consonants.
• Note: Italian has both palatal nasals and palatal laterals.