This script gradually shifts a formant track (here: first formant, F1) to create a phonetic continuum from high-to-low (e.g., from “bet” to “bit”). It takes a list of word pairs as input, reads the first member, and applies the formant shift while controlling for intensity and f0.
You can also download the script as a .praat file.
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### Hans Rutger Bosker, Radboud University
### HansRutger.Bosker@donders.ru.nl
### based on an earlier script created by Matthias Sjerps
### Date: 20 July 2023, run in Praat 6.3.08 on Windows 10
### License: CC BY-NC 4.0
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###>> This script takes pairs of items (e.g., bet and bit) from a directory
###>> that critically only differ in their F1 ("bet" has higher F1 than "bit").
###>> The script then creates a phonetic continuum from high F1 (bet) to low F1 (bit)
###>> using Burg's LPC method.
###>> IMPORTANT: Please provide a list of word pairs in a .txt file in the
###>> input directory. This file should contain two tab-separated columns
###>> with the labels "word1" and "word2". Then script then loops over the
###>> rows in this list of pairs. For example:
###>> word1 word2
###>> bet bit
###>> get git
###>> set sit
###>> IMPORTANT: Every individual sound file should already have an accompanying
###>> .TextGrid file containing one tier. This tier should have 3 intervals:
###>> 1. The interval preceding the critical vowel
###>> 2. The interval of the critical vowel
###>> 3. The interval following the critical vowel
###>> The script includes transplantation of the intensity contour of the original
###>> word1 to the manipulated output sound. The script can also set the
###>> f0 of the manipulated vowel to a fixed average value calculated
###>> across the two members of an item pair. This is done by setting
###>> the variable control_f0$ to the value "yes".
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### Variables you will definitely need to customize:
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### Where can the files be found?
dir_in$ = "C:\Users\hanbos\Desktop\mysounds"
### Where should the output files be saved?
dir_out$ = "C:\Users\hanbos\Desktop\mysounds\continua"
### What is the name of the .txt file containing the list of word pairs?
### NOTE: Do **NOT** include the .txt extension; just the name!
table_name$ = "list_of_pairs"
### Next to the formant manipulations, do you also want to control the f0 and duration
### of the output sounds by setting them to the average value between the two words?
control_f0$ = "yes"
### Number of estimated formants (default: 5)
nformants = 5
### Provide the max. frequency for filtering (default for F1: 3000)
### Manipulations will be performed below this frequency only;
### the original signal is used above this frequency.
### This helps to create natural-sounding (i.e., convincing) output speech.
filter = 3000
### Provide cutoff frequency for formant detection (default: 11000)
cutoff = 11000
### Provide the min and max pitch settings.
### For female talker: 100 - 400
### For male talker: 75 - 300
minpitch = 100
maxpitch = 400
### Define how many steps should be on your continua.
### It helps if this value is an odd number so you have a 'true' average
### in the middle. Default is 11 because this means the steps go up/down
### by 10% every time. This means that step 1 has the mean F1 of the original
### high-F1 member (e.g., bet) and step 11 has the mean F1 of the original
### low-F1 member (e.g., bit).
nSteps = 11
### Define your manipulation method (default: burg)
methodLPC$ = "burg"
### Define your fade-in/fade-out overlap window in seconds (default: 0.01)
window = 0.01
################################################################################
### Let's check whether the directories specified above exist...
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### Let's check if the input directory exists.
### This script will throw an error if the directory doesn't exist
### (i.e., it won't write to a mysterious temp directory).
### First check whether the input directory ends in a backslash (if so, removed)
if right$(dir_in$,1)="/"
dir_in$ = left$(dir_in$,length(dir_in$)-1)
elsif right$(dir_in$,1)="\"
dir_in$ = left$(dir_in$,length(dir_in$)-1)
endif
### Then create a temporary txt file in the folder
### and try to write it to the input folder.
### NOTE: The "nocheck" below asks Praat not to complain if the folder
### does *not* exist. We'll manually check whether the saving of this
### temp txt file has succeeded or not further down below.
temp_filename$ = dir_in$ + "/" + "my_temporary_Praat_file.txt"
nocheck writeFileLine: temp_filename$, "This is just to check if the directory exists"
### Can the file be found?
file_exists_yesno = fileReadable(temp_filename$)
if file_exists_yesno = 1
# if you *could* read that temp txt file,
# this confirms that the directory is valid.
# Then you can delete it.
deleteFile: temp_filename$
else
# if that file wasn't readable, that means that the directory wasn't valid.
printline The folder 'dir_in$' was not found
exit Your input directory doesn't exist. Check spelling. The directory must *already* exist.
endif
## Now re-do this for the output directory:
if right$(dir_out$,1)="/"
dir_out$ = left$(dir_out$,length(dir_out$)-1)
elsif right$(dir_out$,1)="\"
dir_out$ = left$(dir_out$,length(dir_out$)-1)
endif
### Then create a temporary txt file in the folder
### and try to write it to the input folder.
### NOTE: The "nocheck" below asks Praat not to complain if the folder
### does *not* exist. We'll manually check whether the saving of this
### temp txt file has succeeded or not further down below.
temp_filename$ = dir_out$ + "/" + "my_temporary_Praat_file.txt"
nocheck writeFileLine: temp_filename$, "This is just to check if the directory exists"
### Can the file be found?
file_exists_yesno = fileReadable(temp_filename$)
if file_exists_yesno = 1
# if you *could* read that temp txt file,
# this confirms that the directory is valid.
# Then you can delete that temp txt file.
deleteFile: temp_filename$
else
# if that file wasn't readable, that means that the directory wasn't valid.
printline The folder 'dir_out$' was not found
exit Your output directory doesn't exist. Check spelling. The directory must *already* exist.
endif
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################################# SCRIPT #################################
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################################################################################
## Let's clear the Info window so we can print fresh new log data of our stimuli.
## This log prints for each pair of items ("item"), for each created step,
## the original word duration, vowel duration, mean f0, f1, f2, f3 for the 1st member of the item pair
## the original word duration, vowel duration, mean f0, f1, f2, f3 for the 2nd member of the item pair
## the word duration, vowel duration, mean f0, f1, f2, f3 for the manipulated output sound.
clearinfo
echo item step dur_1 voweldur_1 f0_1 f1_1 f2_1 f3_1 dur_2 voweldur_2 f0_2 f1_2 f2_2 f3_2 dur_manip voweldur_manip f0_manip f1_manip f2_manip f3_manip
Read from file... 'dir_in$'\'table_name$'.txt
nItems = Get number of rows
for ItemCnt from 1 to nItems
## Create leading and trailing silence of 0.5 sec to append to the words to
## improve spectral measurements at the onset/offset of the words.
Create Sound from formula... silence1 Mono 0 0.5 cutoff 0
#######################################
## Read and measure acoustics of word1
#######################################
select Table 'table_name$'
word1$ = Get value... 'ItemCnt' word1
word2$ = Get value... 'ItemCnt' word2
Read from file... 'dir_in$'\'word1$'.wav
Rename... word1
sampFreq_1 = Get sampling frequency
dur_1 = Get total duration
int_1 = Get intensity (dB)
To Pitch... 0 'minpitch' 'maxpitch'
f0_1 = Get mean... 0 0 Hertz
select Sound word1
Resample: cutoff, 50
Rename... word1_belowcutoff
select Sound word1
Remove
Create Sound from formula... silence2 Mono 0 0.5 cutoff 0
select Sound silence1
plus Sound word1_belowcutoff
plus Sound silence2
Concatenate
Rename... word1_pad
Filter (pass Hann band)... 0 filter 10
Rename... Low_Part_1
lowInt_1 = Get intensity (dB)
To Intensity... 100 0 no
Down to IntensityTier
select Intensity Low_Part_1
Remove
select Sound word1_pad
To LPC (burg): ('nformants'*2), 0.025, 0.005, 50
select Sound word1_pad
plus LPC word1_pad
Filter (inverse)
Rename... Source_1
select LPC word1_pad
Remove
Read from file... 'dir_in$'\'word1$'.TextGrid
Rename... word1
Shift times by... 0.5
vowelonset_1 = Get start time of interval... 1 2
voweloffset_1 = Get end time of interval... 1 2
voweldur_1 = voweloffset_1 - vowelonset_1
select Sound word1_pad
To Formant ('methodLPC$')... 0 nformants (cutoff/2) 0.025 50
maxForm = Get maximum number of formants
for formCnt from 1 to maxForm
origFormantsArray_1 ['formCnt'] = Get mean... 'formCnt' 'vowelonset_1' 'voweloffset_1' hertz
f'formCnt'_1 = Get mean... 'formCnt' 'vowelonset_1' 'voweloffset_1' hertz
endfor
Remove
#######################################
## Read and measure acoustics of word2
#######################################
Read from file... 'dir_in$'\'word2$'.wav
Rename... word2
sampFreq_2 = Get sampling frequency
dur_2 = Get total duration
int_2 = Get intensity (dB)
To Pitch... 0 'minpitch' 'maxpitch'
f0_2 = Get mean... 0 0 Hertz
select Sound word2
Resample: cutoff, 50
Rename... word2_belowcutoff
select Sound word2
Remove
Create Sound from formula... silence2 Mono 0 0.5 cutoff 0
select Sound silence1
plus Sound word2_belowcutoff
plus Sound silence2
Concatenate
Rename... word2_pad
Filter (pass Hann band)... 0 filter 10
Rename... Low_Part_2
lowInt_2 = Get intensity (dB)
To Intensity... 100 0 no
Down to IntensityTier
select Intensity Low_Part_2
Remove
select Sound word2_pad
To LPC (burg): ('nformants'*2), 0.025, 0.005, 50
select Sound word2_pad
plus LPC word2_pad
Filter (inverse)
Rename... Source_2
select LPC word2_pad
Remove
Read from file... 'dir_in$'\'word2$'.TextGrid
Rename... word2
Shift times by... 0.5
vowelonset_2 = Get start time of interval... 1 2
voweloffset_2 = Get end time of interval... 1 2
voweldur_2 = voweloffset_2 - vowelonset_2
select Sound word2_pad
To Formant ('methodLPC$')... 0 nformants (cutoff/2) 0.025 50
maxForm = Get maximum number of formants
for formCnt from 1 to maxForm
origFormantsArray_2 ['formCnt'] = Get mean... 'formCnt' 'vowelonset_2' 'voweloffset_2' hertz
f'formCnt'_2 = Get mean... 'formCnt' 'vowelonset_2' 'voweloffset_2' hertz
endfor
Remove
#######################################
## Now loop over steps
#######################################
for stepCtr from 1 to nSteps
# NOTE: we take word1 (here: the high-F1 member [bet]) as the basis for the manipulations.
select Sound word1_pad
To Formant ('methodLPC$')... 0 nformants (cutoff/2) 0.025 50
maxForm = Get maximum number of formants
nFrames = Get number of frames
Rename: "New_Form_'stepCtr'"
###############################################################################################################
# if some items need custom formant shifts, you can define an item-specific constant here
###############################################################################################################
constant = 0
# if word1$ = "bet"
# constant = 30
# elsif word1$ = "get"
# constant = 50
# elsif word1$ = "set"
# constant = 40
# endif
## NOTE: we create a continuum starting at the high-F1 member (on step 1)
## gradually going do to the low-F1 member.
stepsize = (f1_1 - f1_2)/(nSteps-1)
Formula (frequencies): "if row = 1 then (self-(((stepCtr-1)*stepsize)+constant)) else self fi"
## You can also control other formants, for instance by setting the F2 to the average of the two vowels
## thus creating an ambiguous F2 in between the two vowels that is fixed/constant at every step.
## For instance:
#ambF2 = (f2_1 + f2_2)/2
#distanceToAmbF2 = f2_1 - ambF2
#Formula (frequencies): "if row = 2 then (self-distanceToAmbF2) else self fi"
## Filter the original source with the new formant filter
select Formant New_Form_'stepCtr'
plus Sound Source_1
Filter
## Restrict to lower-freq content only
Filter (pass Hann band)... 0 filter 10
Rename... word1_'stepCtr'_Low
## Transplant the original intensity contour back onto the manipulated speech
To Intensity... 100 0 no
Down to IntensityTier
Formula... self*-1
plus Sound word1_'stepCtr'_Low
Multiply... yes
plus IntensityTier Low_Part_1
Multiply... yes
Scale intensity... lowInt_1
## Remove leading and trailing silences
Extract part: 0.5, (dur_1+0.5), "rectangular", 1, "no"
Resample: sampFreq_1, 50
Rename... word1_'stepCtr'_Low_nonpad
## Combine with the original high-freq content
Read from file... 'dir_in$'\'word1$'.wav
Rename... word1
Filter (pass Hann band)... filter sampFreq_1 10
Rename... word1_High
plus Sound word1_'stepCtr'_Low_nonpad
Combine to stereo
Convert to mono
Rename... word1_'stepCtr'_manip
Scale intensity... int_1
selectObject: "Sound word1"
Scale intensity... int_1
select Sound word1_'stepCtr'_manip
dur_manip = Get total duration
To Manipulation... 0.01 'minpitch' 'maxpitch'
Extract pitch tier
f0_manip = Get mean (curve)... 0 0
## Set the F0 to the average values across word1 & word2
if control_f0$ = "yes"
newWordF0 = (f0_1+f0_2)/2
f0ScalingFactor = newWordF0/f0_manip
select Manipulation word1_'stepCtr'_manip
Extract pitch tier
Multiply frequencies... 0 1000 'f0ScalingFactor'
f0_manip = Get mean (curve)... 0 0
plus Manipulation word1_'stepCtr'_manip
Replace pitch tier
select Manipulation word1_'stepCtr'_manip
Get resynthesis (overlap-add)
Rename... word1_'stepCtr'_manip
endif
## We've shifted the formants in the entire word but we really only want to keep
## the critical manipulated vowel only. So here we combine:
## 1. the original pre-vowel interval
## 2. the manipulated vowel interval
## 3. the original post-vowel interval
## using a switch (man1Orig0Switch) that starts at 0 (set to original unmanipulated)
## and switches back and forth to 1 (manipulated), then 0, etc.
Read from file... 'dir_in$'\'word1$'.TextGrid
Rename... word1
nInterv = Get number of intervals: 1
man1Orig0Switch = 0
for intervCnt from 1 to nInterv
selectObject: "TextGrid word1"
intSta = Get start point: 1, intervCnt
intEnd = Get end point: 1, intervCnt
if intervCnt = 1
intSta2 = intSta
intEnd2 = intEnd + (window/2)
elsif intervCnt = nInterv
intSta2 = intSta - (window/2)
intEnd2 = intEnd
elsif intervCnt = 2
intSta2 = intSta - (window/2)
intEnd2 = intEnd + (window/2)
vowelonset = intSta
voweloffset = intEnd
voweldur_manip = intEnd-intSta
endif
if man1Orig0Switch = 0
selectObject: "Sound word1"
Extract part: intSta2, intEnd2, "rectangular", 1, "no"
Rename... 'intervCnt'
man1Orig0Switch = 1
elsif man1Orig0Switch = 1
selectObject: "Sound word1_'stepCtr'_manip"
Extract part: intSta2, intEnd2, "rectangular", 1, "no"
Rename... 'intervCnt'
man1Orig0Switch = 0
endif
endfor
selectObject: "Sound 1"
for intervCnt_2 from 2 to nInterv
plusObject: "Sound 'intervCnt_2'"
endfor
Concatenate with overlap... 'window'
Rename... Resynth____'stepCtr'
## Save the final result sound
Save as WAV file: "'dir_out$'\'word1$'_step'stepCtr'.wav"
selectObject: "TextGrid word1"
Save as text file: "'dir_out$'\'word1$'_step'stepCtr'.TextGrid"
# Let's query the F1, F2, F3, F4 for the manipulated vowel interval
select Formant New_Form_'stepCtr'
f1_manip = Get mean... 1 (vowelonset+0.5) ((voweloffset)+0.5) hertz
f2_manip = Get mean... 2 (vowelonset+0.5) ((voweloffset)+0.5) hertz
f3_manip = Get mean... 3 (vowelonset+0.5) ((voweloffset)+0.5) hertz
f4_manip = Get mean... 4 (vowelonset+0.5) ((voweloffset)+0.5) hertz
select Sound Resynth____'stepCtr'
dur_manip = Get total duration
printline 'word1$' 'stepCtr' 'dur_1' 'voweldur_1' 'f0_1' 'f1_1' 'f2_1' 'f3_1' 'dur_2' 'voweldur_2' 'f0_2' 'f1_2' 'f2_2' 'f3_2' 'dur_manip' 'voweldur_manip' 'f0_manip' 'f1_manip' 'f2_manip' 'f3_manip'
endfor
select all
minus Table 'table_name$'
Remove
endfor
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# End of script
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