How to Use Praat for Acoustic AnalysisCreated by Amanda Shultz

About

Section 1

Section 2

Section 3

Links

About this program

Main Target Audience Objectives Orientatio

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Target Audience• This individualized instruction in PowerPoint was

created for graduate students and instructors with a background in phonology and phonetics who want to learn more about acoustic analysis.

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Objectives• After using this instructional tool, you will:• Have a better understanding of what acoustics is and how

it relates to phonology and phonetics• Know how to use the basic functions of Praat• Know how to measure voice onset time (VOT)

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Orientation• This instructional tool may best be used with two computer monitors, one to

view PowerPoint and the other to download the necessary items and use Praat.• Note that there are links to websites. Once you click on a website link, a window will appear

with the website. You will need to click on the PowerPoint screen again to return to this instructional tool.

• There are three sections to this instructional tool:• Section 1: Background Information• Section 2: Using Praat• Section 3: Measuring Voice Onset Time (VOT)

• You can access the three sections from the main menu.• To access the main menu from any page, click the “Main” button in the lower left corner.

• Each section has its own page.• To access the section page of the section you are currently viewing, click the “Sec” button in

the lower left corner.• Each page has navigation buttons.

• Click the “Prev” button to view the previous page.• Click the “Next” button to view the next page in the progression of this instructional tool.• Click the “Back” button to view the last page you saw.

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Need Help?• If you are experiencing problems with this

instructional tool, feel free to email Amanda at shultz1@purdue.edu.

• If you feel like you need more background information, check out the links page here.

• You can also access a helpful Praat beginners’ guide here.

• For technical Praat questions, you can search the Praat manual by clicking the “Help” button, which is located in the object window as shown in the screen shot below.HELP

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Section 1: Background Information

MainWhat you

should know

Praat VOT Helpful Links

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What you should know• Since this

instructional tool is geared to those who already have an understanding of phonetics and phonology, you should be familiar with:• The International

Phonetic Alphabet• The difference between

phonetics and phonology

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Praat

• To put it simply, acoustics is the study of waves. To people interested in speech, acoustics is the study of the sound waves created by human speech.

• For the purposes of this instructional tool, Praat is an acoustic analysis computer program, which is free off the internet. You can use Praat to take acoustic measurements (e.g., pitch of a sound wave) from audio files of speech and to make markings within a text file to label and keep track of the contents of the audio file.

• Praat was designed by Paul Boersma and David Weenick.• You can access their website for Praat here.

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Voice Onset TimeDefinitions needed to understand voice onset time (VOT):• Phonation (Voicing)—vibration of the vocal folds

which produces a periodic waveform• Sound—a vibration that produces a periodic wave

form (phonation/voicing creates a sound)• Noise—a vibration that lacks periodicity (aspiration

creates noise)• Burst—a pressure impulse that can be seen in the

waveform after the release of a stop/plosivePutting it all together:• VOT—the time that elapses between the burst of a

plosive and the onset of phonation.We will focus on the VOT of the plosives /b/ and /p/.Main Sec Pre

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PLOSIVES

Voice Onset Time• Voiced Stops:

• If the onset of phonation occurs first and the burst occurs second, then the VOT will have a negative value or if the phonation occurs at the burst then VOT would be 0 milliseconds (ms). During the time between the onset of phonation and the burst, there should be some periodicity (sound).• Voiced Stops: VOT ≤ 0• E.g., Spanish /b/

• Voiceless Stops:• If the burst occurs first and the onset of phonation occurs second, then

the VOT will have a positive value. During the time between the burst and the onset of phonation, there may be some noise from aspiration, but there should not be any periodicity (sound). • Short Lag/Unaspirated Stops: 0 ms < VOT < 30 ms• E.g., Spanish /p/

• Long Lag/Aspirated Stops: VOT > 30 ms• E.g., English /p/Mai

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Voice Onset Time

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• This diagram represents a timeline in which the mouth closes (“blockage”) and releases.

• The zigzag represents the timing of the voicing.

Section 2: Using Praat

Main Instructions Video 1 Video 2 Assessme

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Instructions: Getting Started with Praat 1) Go to Praat’s website and download the program on your

computer.2) Go to this website and download the sound file labeled

“Plosive1”.3) Save “Plosive1” to your computer in a location that you

will remember.4) Open Praat. The download should have created a shortcut

on your desktop.5) Close the “Praat Picture” window; we will not be using this.6) In the “Praat Objects” window, click “Read.” Then click

“Read from file.”7) Find “Plosive1” in the place where you just saved it. Click

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Instructions:Getting Started with Praat8) “1. Sound Plosive1” will appear in the Objects list as the first item.9) Click the “Annotate” button located to the right of the Objects list. Then

click “To TextGrid…”10)A window entitled, “Sound: To TextGrid” will appear. Just click “OK”. (We

will save naming tiers for another time.)11)“2. TextGrid Plosive1” will appear in the Objects list as the second item.12)Highlight both the sound file and the TextGrid within the objects window.

(Do this by holding shift while clicking or click and then drag your mouse.)13)Click the “Edit” button located to the right of the Objects list.14)Now you will see a new window appear. This shows the waveform and

spectrogram of the sound file as well as the TextGrid which, right now, includes three tiers, labeled 1, 2, and 3 along the left side of this window.

Congratulations, you have now officially opened a sound file/TextGrid in Praat!

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See the “Beginning Praat Video” on the next page for a demonstration of these

instructions.

• Click the “VIDEO” button above to see a demonstration of the previous set of instructions for using Praat.

Video 1“Beginning Praat Video”

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Video 2“Praat Functions Video”

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• Click the “VIDEO” button above to see a demonstration of some of the basic functions in Praat.

Assessment: Using Praat

Click to begin the activity!

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Section 3: Measuring Voice Onset Time

Main Instructions Diagram Video Assessme

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Instructions:Measuring Voice Onset Time1) Find the word that contains the initial stop

consonant that you want to measure.2) Zoom in on the beginning of the word to find the

burst of the stop.• Remember that the burst will make an impulse in the

wave at the beginning of the word.3) Place a boundary where the pulse begins to move

from the dotted blue (zero) line.4) Zoom out to see where the periodicity of voicing

begins.5) Zoom back in to see exactly where the periodicity

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Instructions6) If you are not sure, you can listen to a selection of the speech

that you think should be between the burst and the onset of voicing. Listening with a good pair of headphones is a good way to double check your work.• If VOT is positive, then the onset of voicing should be noise, while the

following vowel should be a periodic sound.• If VOT is negative, then you have a waveform before the burst.

7) Place a boundary at the onset of voicing.8) Click on the space between the two boundary lines and record

the duration. This is the VOT. Remember:• If the burst comes before the onset of voicing, then VOT is positive.• If the burst comes after the onset of voicing, then VOT is negative.• This means that you would have to put a negative sign in front of the

duration that Praat calculated between the onset of voicing and the burst. (There is no reason for Praat to record a negative duration.)

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• The above screen shot of Praat has arrows that point to important features.

DiagramPraat Screen Shot

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Video“VOT Video”

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• Click the “VIDEO” button above to see a demonstration of how to measure VOT in Praat.

Assessment: Measuring VOT

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Click to begin the quiz!

Helpful Links

Praat VOT Video

Praat Website

How to read a

spectrogram

Beginners’ Guide to

Praat

Beginning Praat Video

Sample Sounds

Mystery Spectrogra

mWikipedia:

VOT

Praat Functions

Video

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Wikipedia: Acoustics

• If I wanted to upload a sound file into Praat, what would I click first?

ActivitySection 2: Using Praat

Click on the picture in response to the question.

Correct!

Next Question

• If I wanted to view just the part highlighted in pink, what would I click?

ActivitySection 2: Using Praat

Click on the picture in response to the question.

Correct!

Next Question

• If I wanted to view the Praat manual, what would I click?

ActivitySection 2: Using Praat

Click on the picture in response to the question.

Correct!

Next Question

• Click on the part of the screen that shows the duration of the part of the sound that is highlighted.

ActivitySection 2: Using Praat

Click on the picture in response to the question.

Correct!

You have finished

this activity.

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1. Approximately, what is the VOT for the word “Bat” in the “Plosive1” sound file?

a. 1msb. 4 msc. 12 msd. 51 ms

QuizSection 3:Measuring VOT

Correct!

Next Question

2. Approximately, what is the VOT for the word “Pat” in the “Plosive1” sound file?

a. 88 msb. 62 msc. 54 msd. 10 ms

QuizSection 3:Measuring VOT

Correct!

Next Question

3. Approximately, what is the VOT for the word “Bit” in the “Plosive1” sound file?

a. 85 msb. 72 msc. 35 msd. 13 ms

QuizSection 3:Measuring VOT

Correct!

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4. Approximately, what is the VOT for the word “Pit” in the “Plosive1” sound file?

a. 89 msb. 95 msc. 109 msd. 125 ms

QuizSection 3:Measuring VOT

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