1. Looking at sound Sound can be made visible by waveforms and spectrograms Speech sounds are created by vibrations of the vocal cords, which produce a wave –Variation in air pressure The air pressure can be plotted into a graph to produce a waveform How did we get this wave? Time  Pressure 

2. Production of sound waves by a loudspeaker Sound waves are like waves in a coil (like a Slinky)

3. The individual air molecules only vibrate back and forth locally, they do not travel from the source to the receiver The red line is like your vocal cords

4. Measuring the wave (pressure) Loudness depends primarily on the amplitude

5. Time  Pressure  The sound wave of articulated

6. Complex waves The sound wave of speech is much more complex than the waves we’ve seen so far –The wave of a speech sound is always a combination of multiple other waves with different frequencies and different loudness –These waves are ‘added up’

7. Adding waves

9. This is how a synthesizer works

10. Frequencies To see which sound is produced, we can’t just look at the waveform itself –We need to find the different waves in the waveform –More specifically, we need the frequencies of those waves Frequency is the number of times one wavelength comes by in one second –If it comes by 10 times per second, its frequency is 10 Hertz (Hz) Humans can hear 20 to 20,000 Hz. Most phonetic information is below 8,000 Hz.

11. Which wave has a higher frequency? 0 sec 1 sec2 sec3 sec4 sec

12. Spectrograms The waveform can be analyzed into its frequencies Frequencies can be made visible with spectrograms Time  Frequency  articulated

13. Time  Frequency  Dark areas indicate louder frequencies Voiced sounds have three or four major frequencies F1 articulated F0 F2 F3 əd ɑrɑr thth ɪ k ɾ yu ley

14. əd ɑrɑr Time  Frequency  You can recognize vowels thth ɪ k ɾ articulated yu ley

15. Time  Frequency  You can recognize stops: /p, t, k, b, d, g, ɾ / articulated əd ɑrɑr thth ɪ k ɾ yu ley

16. də Time  Frequency  You can recognize aspiration Little puff of air Big puff of air articulated ɑrɑr thth ɪ k ɾ yu ley

17. Time  Frequency  articulated You can recognize pitch əd ɑrɑr thth ɪ kyu ley ɾ yu ley

18. Which word is this? a.whose b.pseudonym c.judgment d.dessert How did you know?

19. What would you do? Your students consistently pronounce this as /d ɪ s/. Your students consistently pronounce back as /b ɑ k/. Your students have a tendency to insert /ə/ between words in phrases like cold, drink, wet towel, and gas station. A student asks you for advice, saying: “People can’t tell whether I’m saying thirteen or thirty. What should I do?” One of your ESL students has many young American peers who regularly use rising intonation with statements. This student asks you about the conflict between this observation and what has been taught in the class.

20. Next week Submit or hand in midterm assignment –On BB or in class –March 18, at beginning of class Lab session in PH212 at 6:45pm