Calculation on the average time for courses in the incubator to reach beta (part 2)

I did a calculation to find out approximately how long a course takes from entering phase 1 until it reaches beta a little over a month ago and I just thought that with all the new courses that were added, I should revise that calculation. If you are curious about the original, you can find the discussion here: All of these languages are from the incubator:

Here is the revised list for the average. The number of days below is the time from the language entering into phase 1 until it is released in beta. Some of the older courses are approximations because I couldn't find the exact dates in the forums.

<h1>Phase 1 Courses</h1>

For these courses I take duo's estimated date of completion in the incubator and subtract the date the course entered beta.

  • English for Indonesian 188 days 'Estimated completion Apr 24
  • English for Korean 289 days 'Estimated completion Oct 26
  • Spanish for French 96 days 'Estimated completion Apr 26
  • English for Hindi 93 days 'Estimated completion Apr 22
  • English for Arabic 84 days 'Estimated completion Apr 24
  • German for Spanish 92 days 'Estimated completion May 7
  • English for Greek 68 days 'Estimated completion Apr 27
  • English for Vietnamese 91 days 'Estimated completion May 29
  • English for Czech 296 days 'Estimated completion Dec 24
  • Russian for English 264 days 'Estimated completion Nov 30
  • Hungarian for English 3425 days 'Estimated completion Jul 27 '23
  • Polish for English 882 days 'Estimated completion Aug 09 '16
  • Romanian for English (no estimated end date)
  • Dutch for English 566 days 'Estimated completion Sep 28 '15
  • Turkish for English 1225 days 'Estimated completion Jul 18 '17
  • Irish for English (no estimated end date)
  • English for Thai 99 days 'Estimated completion Jul 17
<h1>Phase 2 Courses</h1>

These dates are based on the date entering beta minus the date entering phase 1.

  • English for Russian 66 days
  • English for Dutch 52 days
  • English for Turkish 42 days
  • English for Hungarian 54 days
  • French for Spanish 30 days
  • English for Polish 104 days
  • Portegese for Spanish 43 days
  • English for Romanian 45 days
  • English for Japanese 140 days
  • Spanish for Portegese 27 days
  • German for Russian 62 days
  • French for German 62 days
  • English for Chinese 181 days

So the total average time for a course to enter beta would be 309.5 days.

However some of the new courses are just starting out and are going to be off by quite a bit. In light of this, I did another average limiting the new courses to a maximum of 200 days. This is above the longest course (Chinese at 181 days) so I think this limit is more realistic to expect than 2023! The average with this limit imposed is 114.6 days.

So it seems the average has gone up from the first calculation of 83 days, but its still just over 3 months which seems about what most of the languages here require. I think the extra time is due mostly to the new language contributors (Russian, dutch, Turkish, etc) needing extra time to actually build the tree structure in addition to doing the actual translations.

I hope this is useful information for you. Happy learning!!

April 21, 2014


For some reason I can't edit my original post. Thanks to jitengore and Z.Shan, I have updated the English for Chinese to 171 days and the English for Hindi to 87 days. That puts the average at 307.6 days and the modified average (with 200 days max for the new languages) at 112.6 days.

Here are the dates I am still unsure about in case anyone has any knowledge of when these courses actually started (or went into beta for the Polish course):

  • German for Russian started on Jan 22, 2014?
  • English for Japanese started on Oct 14, 2013?
  • English for Romanian All I have is it started before Dec 21, 2013
  • Portegese for Spanish All I have is it started before Dec 21, 2013
  • English for Russian started week of Oct 14, 2013
  • English for Indonesian started week of Oct 28, 2013?
  • English for Korean started Jan 10, 2014?
  • Spanish for French started between Jan 20 to Jan 22

  • English for Polish started between Oct 21, 2013 to Oct 18, 2013 In beta between Jan 22, 2014 to Jan 26, 2014

All other dates I know the exact date for. 10 lingots for whoever can contribute to refining these unknown dates. Thank you.

<h1>Also the average time before a reverse course comes out is 61.1 days.</h1>

Edit: Also thanks to Selcen_Ozturk for the Turkish update! Turkish remains 42 days but I now know the dates.

April 21, 2014

English for Turkish started on Nov 16, 2013, released on Dec 29 (maybe it was Dec 28 according to US time).

I think Hungarian started on the same day.

and don't worry Turkish for English won't take 1225 days :)

April 21, 2014

Thanks for the update! I figured with you guys being the fastest team when your course came out that you could manage to do the reverse course in less than 4 years! Have some lingots for your trouble.

April 21, 2014

thank you :) just a reminder to everyone, x for English speaker courses will definitely take longer time as there is no ready "skill tree", but they will definitely not take years. We need to plan before we really prepare the course in the incubator.

April 21, 2014

Yeah 42 days would be really tough to beat, especially with the added skill tree work you guys have to do. Its been 41 days so far so you would have to do 98% by tomorrow :D But you guys have surprised us before..... Just kidding. I'm anxiously awaiting it but that would be impossible. Thank you so much for volunteering your time to create these courses. The whole community really appreciates it!!! Good luck with the course!!

It is really incredible how fast all of these courses are being added to the community. Duo really is an amazing place with amazing people!!!

April 21, 2014

10 Lingots? There's a way to tell the exact time and date when a forum post was made. Caution: It's a bit geeky.

If you want to find out when Romanian was added to the incubator, you'd (in Firefox):

  1. Find the forum post announcing it trough the search engine.
  2. Once you have the forum post (e.g., open the web console by pressing Ctrl + Shift + K (Cmd + Opt + K on Mac) or via the web developer menu.
  3. Right-click the large white panel, and ensure that "Enable network request and response body logging" (or something similar) is enabled.
  4. The web console panel has multiple tabs. Switch to the rightmost one: Network monitor.
  5. Upvote the post. In the network monitor panel, a new line will appear.
  6. Click on the new line. The panel will now split into two parts. In the right part, there will be tabs: Headers, Cookies, Params, Response, Timings.
  7. Click on the tab "Reponse".
  8. Enter "date" into the little search box or scroll down to datetime_string.
  9. Voilà! The datestime_string gives you the exact time and date the post was created. For example, Pece created his post heralding the advent of the Romanian course on December 12, 2013, 6:57:57 UTC.

Similarly, in Chrome, you'd go something like Tools -> Developer Tools -> Network -> (upvote) -> (left click on your shiny new upvote) -> Preview. But I don't vouch for it.

In case you're wondering what's actually going on here: When you open a forum post in your browser, your browser sends a request to the Duolingo servers. They answer with an HTML page, and your browser replaces whatever it had been displaying with the new page. As you know, the post date given in the HTML is very inaccurate (e.g. "6 months ago"). But when you upvote a post, Duolingo sends a background request to the Duolingo servers, which they answer with a JSON object. The purpose of the background request is that your browser does not have to replace the entire window content with a new HTML page, but only has to fetch the data it needs. Luckily for us, it fetches the entire post along with lots of metadata. It doesn't display this data, but it still has it. The network monitor allows you to "listen in" on the background traffic that is happening between your browser and the Duolingo servers and to inspect the JSON objects manually.

April 22, 2014

Wow thank you so much for this. I believe this deserves 20 lingots since now I can finish all my unknown dates for all courses. I wish I would have known this a long time ago!! It would have saved me so much time.

April 23, 2014

Thanks! I'm glad it was useful.

April 25, 2014

Russian reached beta on the 19th December, it was the 4th gift

April 21, 2014

That's the exact same date I got. Thanks for verifying.

April 21, 2014

I think Turkish was between 25th and 27th December and Dutch was between the 20th and 23rd, Dutch was 52 days

April 21, 2014

I have Dutch starting the week of Oct 18, 2013 and being 52 days. I know it went into beta between Dec 19 and Dec 31. Do you have a link to reference where you found the 20th and the 23rd?

Edit: Never mind I found the link. Dutch went into beta on Dec 23 and you are correct that is was 52 days.

April 21, 2014

Dutch was a few days after Russian, before Christmas and Turkish was a few days after

April 22, 2014
  • Russian Dec 19
  • Dutch Dec 23
  • Turkish Dec 28

Thank you so much for helping me to find all this information!!

April 22, 2014
  • 1908

Hey, @rajuncajun09! You should try to contact @Usagiboy7, they kept eyes on a lot of discussion threads and should have the information you want. In addition, @J-Steven writes weekly incubator updates, so he may have the record of the dates. Many of the forum moderators have set up a wikia page, in which there is this list of language courses. Thank you and good luck!


April 22, 2014

Thanks for the suggestions. I have used JStevens updates quite a bit over the last few months and have figured out several dates from that. Unfortunately he started them on Jan 19 of this year and all the dates I am missing are from before that date. I will ckeck the wiki that Usagiboy7 created to see if he has any info there. Thanks again for all your help!

April 22, 2014
  • 1908

English for Chinese started on Oct 23, 2013 officially recorded by Duolingo and it entered Beta on Apr 11, 2014 (EST). I think it's 172 days.


April 21, 2014

I have the original release date as Oct 14, 2013. This is a guess based on several discussions, but I believe that date to be accurate. That is how I came up with 181. After a month, the dates become almost impossible to pinpoint exactly unfortunately, so many of the dates for 2013 are plus or minus a week or so. I started keeping track of exact dates around February. Do you have a link for it being on Oct 23, 2013? I would greatly appreciate a definite date for this.

I am 100% sure the beta release was on Apr 12, 2014. All of my dates are based on the date in the United States that the course was released on because that is where the duo headquarters are located.

April 21, 2014
  • 1908

The Duo team told me that date. They kept the record of everything. Luis released the first wave of courses here, but I'm not sure about the date of this post. The only way to figure it out is to wait until the day it changes from 6 months ago to 7 months ago and count back 7 × 30 days I guess. It'll be a huge waste of time and I'd rather trust the Duo team on this. Great work you have collected all the data. 10 Lingots for you! :D

Edit: The Duo staff told us that our course is in Beta at 12:57, Apr 11, 2014 (EST) according to my email. And I woke up here in Hong Kong at around 9:30, Apr 12, 2014 (UTC+8) and checked the incubator, our course was indeed in Beta already. Pittsburgh and I have a time difference of 12 hrs, right?


April 21, 2014

Yea that is the trouble I have had too in finding when the exact dates are. That is why I had to approximate many of the older ones. Thank you so much for helping to refine my dates and for the lingots!!

April 21, 2014
  • 1908

Actually, if it's from Oct 23 to Apr 11, shouldn't it be 171 days? I can't trust my counter app here. It doesn't seem to work properly.


April 21, 2014

After looking back into the discussions, I believe you are correct with the time frame. I knew I might be off with that language by a few days. I will update the data to reflect the 171 days for Chinese. Thank you so much for helping me fine tune the data.

Thank you so much for contributing to the Chinese course. Can't wait for Chinese for English speakers to start!!

April 21, 2014

Hindi reached beta today

April 21, 2014

Thanks, rajuncajun09 for putting this together. I had followed your last post as well where you had predicted Hindi Beta on 21-Apr. That was bang on :) These are the kind of posts which elevate the interest in the community for the incubator languages and motivate their contributors. Kudos to you!

A minor point - our course began on Friday, 24th January, so that makes it 87 days to beta and not 93 as reported here (reported 92 in the past). You might have counted from the beginning of that week, Perhaps?

April 21, 2014

So duo's prediction algorithm seems to be pretty accurate then!! Thanks for the kind words and the clarification. I had narrowed down the start date of hindi to between Jan 19 and Jan 26, but I couldn't find anything to give me a definite date. Thanks for clearing that up for me!! I will be updating the data.

I really enjoy your updates in the incubator. Congratulations on finishing the course. I've been looking forward to it! Have some lingots.

April 21, 2014
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