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ACOUSTIC PHONETICS Seeing & Measuring Speech sounds. Linguistics 187 / Cultural Anthropology 187 / English 187 / ICS 151C Variety in Language: English in the United States Duke University Erin Callahan-Price Spring 2011. I. Whirlwind tour of acoustic phonetics.
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ACOUSTIC PHONETICS Seeing & Measuring Speech sounds Linguistics 187 / Cultural Anthropology 187 / English 187 / ICS 151C Variety in Language: English in the United States Duke University Erin Callahan-Price Spring 2011
I. Whirlwind tour of acoustic phonetics Preparation for Vowel Workshop with Dr. Erik Thomas
Remember Vowels? Our Inventory: American English
What was our Inventory before? The Great Vowel Shift
What happened? What does it look like in articulatory and acoustic “space”?
Vowel Movements The Push-Pull Effect
Contrasting patterns of vowel shifts: Southern Shift vs. Northern Cities Vowel Shift
Great. Relevant social questions for sociolinguists: • Where are these shifts happening, and why? • What can the distribution of the shift(s) tell us about social relationships? • Who talks to who? • Who migrates where? • What happens when non-native English speakers acquire English in a shifted area? Representative social network diagram aggregating connections from Facebook, LinkedIn, MySpace (…) (from Rowse (2007)
Great, cont. Relevant practical (empirical) question for sociolinguists: • How can we accurately and reliably quantify/measure/calculate the acoustic changes constituted by these shifts?
Analyzing speech production with spectrograms: A First Look • The main tool phoneticians/linguists use to measure speech production is a spectrogram, a visual representation of sound.
Information in Spectrograms: Measuring sound through the digitization and Sampling Process
From Power Spectrum to Spectogram In a power spectrum, frequency in Hz is displayed on the x-axis and amplitude is displayed in dB on the y-axis
From Power Spectrum to Spectogram: A First Look In a power spectrum, frequency in Hz is displayed on the x-axis and amplitude is displayed in dB on the y-axis
From Power Spectrum to Spectogram Measuring vowels as rendered on a spectrogram involves measuring their component resonances, or formants (isolated above)
“Zooming In” to Syllable Level • Vowel Plots are produced when the researcher measures the F0 (fundamental frequency) as shown on the spectrogram for, say, ten glottal pulses… • …and then plotssome average of those measurements in a vowel chart.
Finally! Measuring Vowels: the trenches • Formant tracks like this allow us to measure vowels in the speech stream, and compre them across speakers.
Finally! Measuring Vowels: the trenches • After many samples of ONE vowel are taken, we can move to the next vowel… • …and the next…and the next…
Finally! Measuring Vowels: the trenches • Until we have a vowel plot!
Homework • Read C.2 • Download praat: http://www.fon.hum.uva.86nl/praat/download_win.html http://www.fon.hum.uva.nl/praat/download_mac.html • BRING LAPTOPS!
II. USING PRAAT to measure vowels Preparation for Vowel Workshop with Dr. Erik Thomas
Steps to Recording & [vowel] audio for analysis 1. Download & install praat. 2. In “Objects” window: • New Record mono sound • Read word list (heed, hid, hayed, head, had, hod, hawed, HUD, hoed, hood, who'd, hold, heard) • Save to list. 3. Highlight “Sound Untitled” and click “View and Edit”
Analysing your Recording 1. In waveform view, highlight one “chunk” of sound (which is an individual word):
Analysing your Recording 2. Use shortcuts to zoom to navigate praat: a. Highlight + CTRL+N= Zoom to selection b. CTRL+O= zoom out c. CTRL+I= zoom in d. Tab= play or stop
Format Settings 3. At appropriate view (around 2-3 words or so): a. Formants Show Formants b. Formants Formant Settings c. Adjust Formant number from around 4-6 to calibrate formant tracking: TRIAL AND ERROR TIPS: -The goal is for the formant tracking (red lines) to match the sound that you “see” with your eyes. In other words, you want the computer to see what you see. This is a modeling task. -Don’t worry about Formants 3-5+. You’re only measuring 1 and 2.
Measuring the Vowel(s) 4. At appropriate view (around 2-3 words or so): a. Position cursor about in the middle of the selection.
Getting formant values 5. Measuring formants • F1= Get first formant; F2= Get second formant • Record values on paper or in Excel
Plotting values 6. Arrange your axes like this and plot your vowels:
Just for Fun • Manipulating and Synthesizing Sound with praat: • 1. Low/High Pass • 2. “Change Gender” • 3. Pitch Manipulation