Speech analysis with Praat

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Speech analysis with Praat

• Paul Trilsbeek
• DoBeS training course
• June 2007

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Sources used

• Sidney Woods Praat beginners manual
• Pascal van Lieshouts Praat short tutorial
• Links for both on www.praat.org

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Outline

• First half theoretical overview
• What is Praat
• General Praat interface
• Several kinds of analyses
• Creating graphical output
• Second half practice
• Hands-on experience with some exercises

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What is Praat? (1)

• Praat speak (Dutch)
• Doing phonetics by computer
• Analysis and reconstruction of speech signals
• Developed by 2 phoneticians from the University
  of Amsterdam, Paul Boersma and David Weenink

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What is Praat? (2)

• Program running on most operating systems
  (Windows 95 to XP, Mac OS 9/X, Linux, several
  kinds of Unix )
• Available for free from www.praat.org under GNU
  General Public License (inc. source code)

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General Praat interface

• Praat objects window
• List of praat objects sounds, analyzed sounds,
  synthesized sounds
• Buttons for editing, viewing, applying analyses,
  etc.
• Praat picture window
• For creating and manipulating graphical output

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General Praat interface
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Getting help

• Praat help menu
• Praat web site (same content)
• 2 tutorials mentioned before (see praat.org)
• Praat discussion list

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Recording a sound
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Loading a sound

• Long vs. short sound file memory
• Extract part
• Extract segments from annotated long sound

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Annotating a sound

• Create text annotations on different levels
• Praat objects can be created from segments

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Annotating a sound
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Praat Edit window

• Waveform display
• Segment play buttons
• Zoom buttons
• Several other views of analyses
• Spectrogram
• Pitch analysis
• Intensity analysis
• Formant analysis
• Pulses

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Praat Edit window
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Spectral analysis

• Fourier theorem any given signal can be
  constructed by addition of an infinite number of
  sine waves with specific frequencies, amplitudes
  and phases.
• Fourier analysis finding out the frequencies,
  amplitudes and phases of these sine waves for a
  given signal

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Spectral analysis
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Spectral analysis
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Spectrogram

• Spectrum with a third dimension added time.

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Pitch analysis

• Shows fundamental frequency where one can be
  detected
• Not always correct, octave jumps often occur,
  depending on the quality of the signal. Can be
  corrected manually.

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Pitch analysis
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Intensity analysis

• Shows the intensity contour of a signal

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Intensity analysis
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Formant analysis

• Frequency bands with higher acoustic energy
  caused by resonances in the vocal tract, mouth
  and nose cavities
• Different vowels and fricative consonants have
  different formant structures

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Formant analysis
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Manipulation

• Add or delete pulses
• Modify duration (timing)
• Modify pitch contour

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Manipulation
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Picture window

• Clicking draw button will draw graphic into
  picture window
• Some modifications can be done in the picture
  window
• Text can be added

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Picture window
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Picture window

• Export picture as EPS (Encapsulated PostScript)
  for further use in media to be printed. Adobe
  Illustrator can be used to further edit the EPS
  file
• Export picture as Windows Meta File (Windows
  only) for media to be shown on screen (PowerPoint
  presentation)

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Picture window

• EPS output

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Picture window

• WMF output

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Exercises