The Spaced Repetition System (SRS): Memorization for Life

The initial research on spaced repetition dates back to the 19th century. The German psychologist, Hermann Ebbinghaus, created a long list of nonsense syllables (e.g. daus, dor, gim, ke4k …) and memorized them over the course of 1 year, keeping a record of his progress and using various learning methods. To verify his results, he repeated the same experiment 3 years later. From this experiment, he formed the earliest notions of learning curves, forgetting curves, and spaced repetition.

It took nearly a century of research (by scientists like Wozniak) to model the forgetting curve mathematically and create an effective algorithm to present information for revision at the right moment, while adapting to users’ needs and the level of difficulty.

spaced repetition system

Spaced Repetition System: The Secret to Achieving the Most Effective Memorization Possible


The spaced repetition method of memorization is based on the forgetting curve and on the fact that there is an ideal moment to review information you have learned.

If you review information too early, you’ll waste your time; if you review information too late, you will forget it and will have to re-learn it. In fact, the best time to review information is just before you’re about to forget it. Evidently, it is hard to predict when that time will be, and the time will differ for each person and each piece of memorized information. However, computers (or smartphones, such as the iPhone) have made it possible to predict the ideal time for revision.

This one-minute video explains the concept of spaced repetition system:

Spaced repetition system diagram:

spaced repetition system

As you can see in the diagram, you are likely to forget information very quickly if you memorize it only once.

For your 1st Revision, the spaced repetition algorithm will present you with information to review shortly after you learned it (between 7 and 24 hours, depending on the level of difficulty). Note that the second curve (in red) is already less steep than the first.

The algorithm will present you with information to review less and less often, unless you have difficulty remembering it.

As opposed to cramming in a short amount of time, this is an ideal revision method—it takes little revision (and little time) to store the information in your long-term memory.

MosaLingua’s Spaced Repetition System

The MosaLingua applications for smartphones implement Wozniak’s algorithm. For decades, Wozniak studied and improved these principles. Then, he created a company to market the program SuperMemo, which was very successful, especially for learning reputedly difficult information (Japanese, Medicine, etc.).

Then, Wozniak published his algorithms, and a number of programs were subsequently developed. The best program to date is called Anki. But Anki is complicated, and suggests ready-made lists for users to download, but the lists are not necessarily high in quality, there are no audio recordings, and the words are not organized according to frequency of use. Not to mention, the iPhone version of Anki costs around 15€ …

MosaLingua uses the same algorithm, has lists of vocabulary and phrases that were created by professors, and features high-quality audio pronunciations for each flash card. Furthermore, MosaLingua has many additional features related to language learning (bonus material, learning tips, short lessons, etc.). We have made all of this available for under 5€ in order to reach as many people as possible.

Now where I come in …

Before my trip to Latin America, I used the Anki software on my PC to learn approximately 500 flash cards made up of Spanish words and phrases. Using the software—to my surprise—made it possible for me to communicate during my trip from day one. I had begun using the software 2 months before the trip, spending around 5 to 10 minutes per day on revision.

spaced repetition system

The part that took me the longest was compiling a list of vocabulary and inputting it into the Anki software. What’s more, I realized once there that my list needed some work—some words could be removed and some could be added to it. I improved the list during my trip, and upon my return, I worked extensively with a Spanish professor to improve it even further. By the end, this list was made up of over 3000 words and phrases, organized into 15 categories and sub-categories, and ordered according to usefulness (see the list of the most useful vocabulary). I went on to develop an iPhone application for learning Spanish and worked hard with other professors and travellers to adapt this list for other languages (English, Italian, French, German, etc.). If you would like to know more, please don’t hesitate to read this description.


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    • I want to learn Spanish, but I want to learn the Spanish spoken in Mexico, rather than the ‘peninsular’ Spanish of the EU. Will your program work for me? Also, please don’t forget the folks who prefer a more open source approach than Apple, and a huge consumer demographic; those who use Android. Do you have an app for this portion of the consumer market?


      • Hello and thanks for your comment. We offer vocabulary from both Latin America and Spain, however we don’t necessarily have specific Mexican terminology. We try to teach the most commonly used terms/phrases from the region. Also, the MosaLingua apps are available for Android as well as Apple. Please do not hesitate to contact us at with any additional questions or concerns.


  1. Hello,
    I bought Mosalingua from the appstore, and it is really great, during the last 3 months I learnt about 900 flash cards, but I want to ask you; is there a way to copy the flash cards of Mosalingua to Anki on my PC?

    Sometimes I want to learn from my PC and I want to put Mosalingua flash cards along with my other flash cards in Anki. If there a way to do that please tell me how.

    Thank you

    • Hello,
      No, sorry, it’s not possible, but we are working on a web version of MosaLingua that will be released this year.
      Hope this help,
      Best regards,

      • Any update on the web version? This would be very useful!

        • Hi Patrick,

          Thanks for your sharing your opinion!
          Yes, we are working on it. We are going to create a poll on the website so you will be able to add your suggestion.

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