Basic guide to using Praat for acoustic phonetic analysis
Setting up your "lab"
To use Praat on your home computer, you can download it from its website, at http://www.fon.hum.uva.nl/praat/
. In a lab on campus, such as Ballantine 108, you can use the following instructions.
- Plug in the headset. The green plug goes in the port with a picture of headphones and the pink plug goes in the port with a picture of a microphone.
- Adjust the volume. Unmute the volume on the computer, turn the volume knob on the headphone cord to maximum, and adjust the volume on the computer until it's comfortable. You may wish to adjust it further later.
- Start Praat. It can be found under "All Programs" > "Departmentally Sponsored" > "Linguistics".
Recording a sound
- In Praat, click "New" > "Record mono Sound..."
- Enter a name for the recording in "name"
- Click "Record". Click "Stop" when you're done. Clicking "Record" again will replace your last recording with a new one.
Make sure you speak clearly and not too quietly. Also make sure you have the microphone far enough away from your mouth that you don't get red bars during the recording. If you get red bars, click "Stop", adjust the microphone, and try again. If you continue to get some red bars, just continue with the assignment, but know that you may have to re-record the sound if you're having trouble measuring things.
- Click "Save to list & Close" to load the recording into the Object list
With any measurement, Praat is likely to give you a very exact number. As a general rule, you don't want to care about more than about one decimal place in frequencies (e.g., 461.5Hz) or more than 4 decimal places in seconds / 1 decimal place in milliseconds (0.0225s, or 22.5ms).
To prepare your environment in Praat to measure something, start by doing the following:
- Click on the sound you recorded in your Object list, and click the "View & Edit" button.
- Select a smallish section of audio (e.g., a word) that contains what you want to measure, and click "sel".
- Make sure "Formant" > "Show formants" is selected. The red dots are formant measurements. They should more or less line up with the formants (dark horizontal bars) in the spectrogram. If they don't, you may need to adjust your settings some.
- To measure a formant, click on or near a red dot. The frequency (in Hertz) at the place you clicked is displayed on the left in red characters.
Measuring fundamental frequency
- Make sure "Pitch" > "Show pitch" is selected. The blue dots (and line) are pitch / fundamental frenquency measurements. By default, they don't line up with anything, but they should be contiguous for any vowel (where it's easiest to measure fundamental frequency).
- To measure the fundamental frequency of a vowel, click on or near a blue dot in the vowel. The frequency (in Hertz) at the place you clicked is displayed on the right in blue characters.
Measuring vowel length / duration
- After zooming in to the word you're looking at, select the entire length of the vowel you want to measure. You can hear if you've selected the entire vowel by clicking the gray bar below the spectrogram that corresponds to the selection. That gray bar also includes the length of the selection (i.e., the length of the vowel) in seconds. If you're not zoomed in close enough to your selection, you may miss some digits; if this is the case, just click "in".
- Identify / locate the aspriation noise. Select it as with vowel length to view its length / duration in seconds.
Saving your recordings
- In your objects list, select the sound recording that you want to save.
- Click "Save" > "Save as FLAC file..."
- Choose a location and filename for your file.
- Repeat for any other recordings you want to save.