Achieving fluid, native-quality speech in a second language is difficult task for adult learners. For several years, I’ve used Dr. Olle Kjellin’s method of “chorus repetition” for my Russian language study. In this post, I’m presenting a method for scripting Audacity to facilitate the development of audio source material to support his methodology.

Background

For detailed background on the methodology, I refer you to Kjellin’s seminal paper “Quality Practise Pronunciation with Audacity - The Best Method!” on the subject of chorus repetition practice. The first half of the paper outlines the neurophysiologic rational for the method and the second half describes the practical use of the cross-platform tool Audacity to generate source material for this practice.

Rationale for this project

Preparing source material (sentences of about 2 seconds duration) for this method is not difficult, but the steps are repetitive. Fortunately Audacity offers the ability to script its behaviour through macros (Tools → Macros...). Two macros are described here. Neither are complex, but they do chain common commands in Audacity, making it faster to produce material for chorus repetition. The first macro just trims silence from the clip and compresses its dynamic range. The second takes a clip, ideally a single sentence, adds 0.65 seconds of silence at the end, then replicates the clip + the silence 5 times for a total of 6 repetitions.

Macros

Truncate and compress

To install this macro, download the file (Download ZIP.) On macOS, you can move the file to ~/Application Support/audacity/Macros. I’m not sure where it goes on other platforms; check the manual.

To use the macro, start with the sentence clip you want to process and invoke Tools → Apply Macro → TruncateAndCompress.

You can play around with different parameters if you need to trim more or less silence or if you want to change the compressor settings.

Kjellin Sentences

This macro will take a prepared clip, ideally a single sentence and create six total iterations with 650 ms of silence between each iteration.

To install the macro, download it from the following location using Download ZIP, decompress and place in the Macros directory as above.

You will need one additional step before this is usable. You will need to create a user preset for the Generate silence tool. Navigate to Generate → Silence... and create a preset named “650ms” so that the macro can use it.

Again, to use it, just prepare a track with a single sentence you wish to use and then Tools → Apply Macro → KjellinSentences.

Enjoy and keep practicing!

This is an update to my previous post on automating iTunes on macOS to support chorus repetition practice. You can read the original post for the theory behind the idea; but in short, one way of developing prosody and quality pronunciation in a foreign language is to do mass repetitions in chorus with a recording of a native speaker.

Because in macOS 10.15, iTunes is no more, I’ve updated the script to work with the new Music app. It turns out that it’s a lot simpler. No need to dive into the application classes.

--
--	Created by: Alan Duncan
--	Created on: 2020-07-04
--
--	Copyright (c) 2020 OjisanSeiuchu
--	All Rights Reserved
--

use AppleScript version "2.4" -- Yosemite (10.10) or later
use scripting additions

property trackDuration : 1
property minimumVolume : 10

--	initial volume, set by user
global volume0, trackRepeatMode0

on run
	
	tell application "Music"
		-- save original settings
		set trackRepeatMode0 to song repeat
		set song repeat to one
		set volume0 to sound volume
		
		play
		
		--	calculate the delay between fades
		set fadeDelay to (trackDuration * 60) / (volume0 - minimumVolume)
		repeat with i from minimumVolume to volume0
			delay fadeDelay
			set sound volume to sound volume - 1
		end repeat
		
		pause
		-- restore original settings
		set song repeat to trackRepeatMode0
		set sound volume to volume0
	end tell
	
end run