Homework #4:  Speech Acoustics

Linguistics 103
Bruce Hayes
Department of Linguistics
UCLA

1. Fundamental frequency.  Look at this waveform:

You can hear what is being said by clicking here.  

a. Pick some interval of time, and count all the vocal cord vibrations that occurred in it.  Specify your interval (beginning point, end point), and how many vocal cord vibrations you counted.

b. Given what you just said, do the arithmetic and figure out what is the time needed for one vocal cord vibration.  Show your work.

c. At this pitch, how many vocal cord vibrations would occur in one second (or, to ask the same question in different terms: what is the frequency of the voice in Hertz?)

d. Answer the same questions for the following waveform (the sound is like this):

e. Does the following waveform show rising pitch or falling pitch?  Explain your answer briefly.

2. Aspiration.  This will be easier if you read Chapter 6 of the text first.

Listen to these waveforms:    A Nye spot   B. nice pot  (Nye is the name of one of the counties of Nevada.)

You can hear the waveforms here and here (but I'm not telling which order they occur in!).

Which of these figures is the waveform for A, and which for B?  Justify your answer.  

I.  ANye.jpg

II. SomeOtherNye.jpg

3. Intonation.  Listen to these two wave forms:  A   B.

Which of these figures is the pitch track (displaying frequency) for A, and which for B?  Justify your answer.  Note that each pitch track shows a mini version of the waveform above it.

I. AnIntonation.jpg

II. SomeOtherIntonation.jpg

4. Vowel Formants. Below are displayed spectrograms are of me saying seven vowels. These vowels are (not in this order):

The vowels sound like this: 

[i]
[e]
[epsilon]
[a]
[open o (backwards c)]
[o]
[u]

Here are the spectrograms, given in random order.  What you see is a fairly small spectrogram; click on each to get a bigger version.

I. VowelSpec1.jpg

II. VowelSpec2.jpg  

III. VowelSpec3.jpg

IV.  VowelSpec4.jpg

V.  VowelSpec5.jpg

VI.  VowelSpec6.jpg

VII.  VowelSpec7.jpg

State which vowel corresponds to which spectrogram. You should be able to do this by comparing the spectrograms with each other and examining the first and second formants.  Explain in general terms how you linked up the spectrograms to the vowels.

It may also help to examine the spectrograms in Figure 8.3 of the text, which, if I remember correctly, are from my own speech. However, bear in mind that the Fig.8.3 vowels are real vowels of American English occurring in the frame  

/ h ___ d

whereas the vowels in this homework are my attempt to produce typical monophthongal vowels as they occur in other languages.

Two hints:

• In #2 and #4, the first two formants are very close, so there is no space between them.
• You might try answering question 5 first.

5. Plotting Vowels on a Chart

Estimate the first and second formant frequencies for all seven vowels given above. To get an accurate formant measurement for a vowel, look in the middle of the dark band. Remember that formants are numbered from the bottom up. You can get an idea of how to measure formants by comparing Figs. 8.2 and 8.3 in your textbook.  State your answer as a table, like this:

Once you've filled out this table, make a printout of p. 190 of your textbook (you can print it from the CD, or from this link).  On this printout, plot the formant measurements. Label them with the right vowel symbol, imitating Fig. 8.5 of your textbook.

6. Using formant transitions to determine place of articulation

In the following three spectrograms, the consonant is either [b], [d], or [g]. The vowel on either side of the consonant is a schwa. Determine which spectrogram has which consonant. Hint: compare these with the spectrograms in Fig. 8.7 of your textbook.

You can hear the sounds here, but not necessarily in the same order as the spectrograms:  [b] [d] [g]  

I.  ConsonantSpec1.gif

II.ConsonantSpec2.gif

III.ConsonantSpec3.gif

8. Sibilant Fricatives

In this spectrogram, the vowels are all [a]. One fricative is [s], the other is . State which fricative came first. Also, explain how you know, quoting appropriate words from the Ladefoged text.  Note that the vertical axis is shown going all the way up to 8000 Hz, to help show the fricatives' full spectrum.

Sibilants.jpg

9. Spectrogram Reading

Multiple choice.  Explain each decision you make.  

BoatwightLittle.png.   Click on the spectrogram to see a bigger version.

10. Speech Analysis

This question is to give you practice in using Wavesurfer; I'm hoping this will help you in making accurate transcriptions for your term paper.

To get help with Wavesurfer, consult the old handout, posted at http://www.linguistics.ucla.edu/people/hayes/103/wavesurferhints.htm

Download this waveform to your computer:  Pie.wav

a. Open it with your copy of Wavesurfer, and make a display that includes (a) waveform; (b) spectrogram; (c) pitch track.  Make a screen clip and paste it into your submitted homework.  Email me if you are stuck doing this.

b. Examine the spectrogram and calculate the VOT (Voice Onset Time, Ladefoged Chapter 6) of the initial /p/.  This is easily done if you highlight the VOT interval with your mouse and read the figure from "Length" at the bottom of the screen.  This is given in seconds, so multiple by 1000 to get milliseconds.

c. Use the mouse to highlight the first 100 msec of the diphthong and say what vowel you hear.

d. Use the mouse to highlight the last 100 msec of the diphthong and say what vowel you hear.

Last updated November 19, 2007