Posts Tagged ‘timestretching’

Practice Chinese Stroke Order at varying speeds

Here we are providing over 80,000 animated GIF files for you to practice Chinese Stroke Order at varying (hopefully increasing) speeds of your choice (millisecs denotes the time you have for each stroke): strip, 1010millisecs, 1000millisecs, 990millisecs, 980millisecs, 970millisecs, 960millisecs, 950millisecs, 940millisecs, 930millisecs, 920millisecs, 910millisecs, 900millisecs, 890millisecs, 880millisecs, 870millisecs, 860millisecs, 850millisecs, 840millisecs, 830millisecs, 820millisecs, 810millisecs, 800millisecs, 790millisecs, 780millisecs, 770millisecs, 760millisecs, 750millisecs, 740millisecs, 730millisecs, 720millisecs, 710millisecs, 700millisecs, 690millisecs, 680millisecs, 670millisecs, 660millisecs, 650millisecs, 640millisecs, 630millisecs, 620millisecs, 610millisecs, 600millisecs, 590millisecs, 580millisecs, 570millisecs, 560millisecs, 550millisecs, 540millisecs, 530millisecs, 520millisecs, 510millisecs, 500millisecs, 490millisecs, 480millisecs, 470millisecs, 460millisecs, 450millisecs, 440millisecs, 430millisecs, 420millisecs, 410millisecs, 400millisecs, 390millisecs, 380millisecs, 370millisecs, 360millisecs, 350millisecs, 340millisecs, 330millisecs, 320millisecs, 310millisecs, 300millisecs, 290millisecs, 280millisecs, 270millisecs, 260millisecs, 250millisecs, 240millisecs, 230millisecs, 220millisecs, 210millisecs, 200millisecs, 190millisecs, 180millisecs, 170millisecs, 160millisecs, 150millisecs, 140millisecs, 130millisecs, 120millisecs, 110millisecs, 100millisecs, 090millisecs, 080millisecs, 070millisecs, 060millisecs, 050millisecs, 040millisecs, 030millisecs, 020millisecs, 010millisecs.   chinese-stroke-order-timestretched-blog-example

Downloading the originals from the most helpful site (also available by direct download) created by Tim Xie for the California State University, Long Beach, and applying my  bash shell script from here, then generating your own speed-differentiated versions, seems to difficult for most users. Even better, instead of perusing the above links, you could just hit my server once and download the whole lot of post-processed animated Gif files with different speeds from here.

Slowing source audio for interpreting classes in the digital audio lab

  1. To judge from listening to Simult. Lesson 1, text 2 on Acebo Interpreter’s Edge (ISBN 1880594323), I am wondering  whether some of our students (= personalization) would need this audio to be simplified, to gain the benefit of a well-adjusted i+1?  I can pre-process the audio :
    1. Where the flatlines = natural pauses are in above graph, insert a audio signal as where students can press voice insert recording,  Example: clip_image001
    2. We can also  insert a pause and a cue at the beginning and end to set students a limit how long they can interpret, but if students operate  the player manually, there is no teacher control and no exam condition, and the students having to manage the technology tends to distract from the language practice.
    3. Slow down the audio without changing the pitch (just have to make sure not to overdo it, else will sound like drunken speech  – my time stretching software would be able to avoid “drunken speech” syndrome, but I have not been able to work on it since briefly for IALLT in Summer 2011 for 3 years now…)
      1. clip_image002
      2. clip_image003
    4. We can use this adjusted with the Sanako grouping feature to personalize instruction (find the right i+1 for each of your student, useful if there are considerable variations in their proficiency): How to group students into sessions  (in 3 different ways)

How to get started with the new text-to-speech support in Sanako 7

  1. With the new text-to-speech feature, students can generate their own pronunciation help:
  2. sanako-tts-1
  3. sanako-tts-2
  4. Using the button:Advanced settings, you can even
    1. vary the speed of,
    2. insert bookmarks to use with Sanako player
    3. or insert thinking pauses for the learner into the audio – excellent ideas, I find Smile!
  5. Unfortunately, the LRC currently has voices only for English and Mandarin. Extra voices cost extra Sad smile.
  6. Then there is Google translate text-to-speech, but that cannot be saved to file.

Learn Chinese character stroke-order with slowed-down animated GIFs

Further to our prior tips on learning Chinese stroke order, now you can take your time, in the LRC: To facilitate your practicing of Chinese character stroke-order, we have used the most helpful site (also available by direct download) created by Tim Xie for the California State University, Long Beach, to create 100 different speed versions, and one comic strip like static image, for each of the several hundred of animated GIFs demonstrating Chinese character writing, and made them available on the LRC computers under Internet Explorer Favorites – Example:


You can access the files with the stroke order speed of your preference from the LRCCOED434 student computers, like so:


(Many thanks also to the authors of programmable ImageMagick image editor and corresponding Unix shell scripts that we could use in the production of the slowed down animated GIFs. To create your own version of these slowed down animated GIFs, or others similar websites, feel free to pick up and/or adapt our shell script here).

IALLT 2011 Presentation on Batch-produced time-stretched audio for personalized language learning

Batch-produced time-stretched audio for personalized language learning  has been accepted for inclusion in the program for IALLT 2011, June 21-25 at the University of California – Irvine and was presented on June 23:

Pervasive networked digital media (both digitized mass media and pod- and tube-casts)  and the build-up of higher education technology infrastructure (classroom management systems, eRepositories, ePortfolios) during what might become the next bubble could form much improved learning environments, if it were not for the impedance mismatch of systems integration challenges. The current challenging financial times can remind us of the original promise of e-learning: increased efficiency. Rapidly expanding second language programs (here English, Spanish and Mandarin) need scalability through automation of learning material provision. Smaller or shrinking programs (here German, Russian, Farsi), where widely differing learner proficiency is increasingly becoming a problem when trying to form classes, need to cope with fragmentation of learning material provision in a “long tail”-economy. Both would benefit from a personalization of instruction that takes into account individual skills, needs and interests. This paper’s software can batch-produce from mp3 and wma input files a user-adjustable range of audio output speeds (see options GUI at and – for a more natural sounding output than the time-stretching mechanisms commonly built into current media players – differentiate between language and pause segments in the input when time-stretching (see samples at The paper will demonstrate such time-stretched audio in a variety of languages and from both SLA and authentic materials and its use, as one step towards more comprehensible input of level “i+1” in a more personalized language learning provision.


I am grateful for being able to attend so many interesting workshops, posters and presentations on new developments in teaching material production, online distance education, ePortfolios, learning center design and management.

As well as the booths of professional organizations, educational software and content vendor.`

CIMG2155 Stitch

And another idea worth emulating were the ZotWheels bike rent stands Smile.

CIMG2209 Stitch

Poster on time-stretching audio @ NEALLT 2011

A wealth of authentic audio materials on the Internet are still out of reach for language learners, and an abundance of textbook materials not as personalized to the learners’ needs as they should since their audio speed cannot be adjusted in a naturalistic way. This poster presents a software that can batch-produce from mp3 and wma input files a user-adjustable range of audio output speeds and – for a more natural sounding output than the time-stretching mechanisms commonly built into current media players – differentiate between language and pause segments in the input when time-stretching: Time-stretching audio POSTER (big)

Language-Learning-Audio-Stretcher II: Samples

What does the Language-Learning-Audio-Stretcher introduced in an earlier blog post do to an audio file you feed in?

For illustration purposes, let’s have a look at a segment of a news broadcast. The example is(taken from the daily Langsam gesprochene Nachrichten by Deutsche Welle: a nice service of slowly spoken news for language learners – in my experience, however, not spoken slowly enough for North-American German students.

This timeline (X axis) shows what a computer program has automatically detected as pauses of varying length (Y axis) in the audio. Depending on a (safety) threshold which the user sets (manually, or, from experience, stored and loaded from a configuration file) in the dropdown boxes of the lower dialogue, the program attacks pauses from a certain threshold value up only: Centre_overall-numerical-data-researching

The segment below consists of a single sentence about peace negotiations with North Korea. It is shown in the following screenshot.

  • 1: transcript of the original audio file
  • 1a: audio graph of the original audio file
  • 2: transcript of the stretched audio file. A new line in this transcript represents a pause inserted by the software.These pauses should aid language students in review the utterance last heard in memory, and hopefully parsing it correctly.
  • 2a: audio graph of the stretched audio file.
  • 2b: note: non-flat audio is stretched
  • 2c: note: flat lines show the pauses inserted, on top of stretching the audio.

Hearing is believing:

This software can be applied to any of numberless public domain audio books (see Project Gutenberg or Wikipedia,  audio books, as well as other free audio book sources) in mp3 or wma format (other formats can be converted). It can also can be applied to commercial audio books, if you have proper licensing.

The software comes with many options that allow you to tweak the output to your liking and needs, see prior blog post.


Time-stretched (-expanded or -slowed, versus, after “negative stretching”, sped-up or “compressed”) audio is of obvious benefit to language learners during listen comprehension skill training exercises, as well as other audio-lingual activities (commonly associated with non- or virtual (online) “language labs”) and an affordance of digital audio media.

As well as compressed audio, especially for repetitive audio-lingual exercises, beyond the obvious possibility of fitting more content into the same time frame since “listeners can process at a much higher rate than normal conversational speech, with some loss of comprehension” (see Roby (1996), Auditory Presentations and Language Laboratories. Handbook of Research on Educational Communications and Technology, 821-850).

Roby, W.B. (2004). Technology in the service of foreign language teaching: The case of the language laboratory. In D. Jonassen (ed.), Handbook of Research on Educational Communications and Technology, 523-541, 2nd ed., 526f. summarizes language learning applications of the “technical advance [of the] speech compressor–expander. This device allowed a recording to be sped up(com-pressed) or slowed down (expanded). Articles on this technology were numerous in the general educational literature from the start of the decade. Sanford Couch (1973),a professor of Russian, advocated its use. Paradoxically, it was not until 1978 that anything on speech compression appeared in the NALLD Journal (Harvey, 978). One would have expected a greater enthusiasm for this feature among language laboratory professionals. The ability to slow down a tape would seem to be a boon to students struggling with a difficult passage. Moreover, variable speed technology was not unknown in foreign-language / teaching, for Hirsch 1954) had commended the use of the soundstretcher (p.22) in the early 1950s. “

The application pictured above simplifies common audio-material producing tasks involving slowing or speeding up (or both) digital audio, with a twist: It allows for pauses being stretched more than non-pauses, thus remediating the common disadvantage of common time stretching applications that – even though pitch is now routinely maintained when altering the speed of digital audio – the result can remind one of drunk speak.

I hope this will help you use more of the many authentic foreign language audio materials available free on the internet.