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This section answers some questions about the course creation process.

Language Courses.png

What is the language Incubator?[]

Main article: Incubator
The Duolingo language Incubator is where bilingual volunteers from around the world connect to build new language courses for Duolingo.[1]

When will Duolingo teach language X?[]

The choice of languages being added to the incubator depends on a lot of factors including Duolingo's internal knowledge of them[2][3].

How long does it take to make a course?[]

According to Duolingo's communication[4], it takes on average 3 months to create a beta course.
However, the statistics over the 84[5] courses created in the Incubator give an average of 331 days (approx. 11 months) to create a beta course. Among those, 19 took less than 3 months to be created as beta course, 11 others took less than 4 months and the 54 other ones took more than 4 months (and up to 4 years).

When will a reverse course be added?[]

Reverse courses are added based on Duolingo's decision making process.

How does Duolingo decide which course to add next?[]

According to CEO Luis von Ahn:[6]

We look for a few things:

  • The number of qualified candidates to build the course.
  • The number of people who want to learn the language.
  • How easy it will be to build the course with our current tools.

How do I apply to create a course teaching language A to language B speakers?[]

The list of languages along with the "Enter Other" option.

If you're fluent in both languages, you can apply to help create a Duolingo course on the incubator website. If the language you want to teach to or from is not listed in the drop-down menus, select "Enter Other" and type it in.

I want to help create courses in both directions between two languages. Do I need to apply separately for each direction?[]

No, you only need to apply for one of the directions. The Duolingo staff will review applications for both directions when assembling a team for either direction.[7] Much of an original course's content will also be used to create its "reverse course",[8] so by contributing to one course direction you will also be contributing to the opposite direction as well.

Why haven't I heard back on my application yet?[]

Duolingo is rolling out new Incubator courses slowly at first, so it may take some time before they are ready to incubate the course you applied for. They are also receiving thousands of applications for Incubator contributors and those take some time to go through.[8]

What is the minimum number of contributors required?[]

Duolingo will always require 2 qualified moderators per course[9].

What is a "beta" course?[]

It means that it's a relatively new course and there might be some errors, so it's going through a "beta" or testing phase before it's "officially" released. Anyone can sign up to take a beta (Phase 2) course on the website.

How long does a course stay in beta (Phase 2)?[]

How long courses stay in beta will vary, but the average duration is 7 or 8 months.

How does a course graduate from beta?[]

A course typically graduates from beta when the Duolingo team and the incubator contributors believe a course is stable[10] and receives less than 3 reports per 100 users.[11]


  1. Duolingo Launches Language Incubator (TechCrunch). Retrieved 2015-05-22.
  2. "Luis Duolingo Ceo, "we're balancing a lot of different factors for the initial languages, such as our own internal knowledge of them","Incubator Updates!".Retrieved 2015"
  3. https://www.quora.com/Why-arent-there-more-rare-languages-on-Duolingo
  4. Duolingo UGC challenges
  5. Course_list. As of 04 July 2019.
  6. Reddit, "IAm Luis von Ahn, co-founder and CEO of Duolingo. AMA.", Luis von Ahn, April 14, 2014.
  7. Incubator: Are you supposed to submit applications for both directions?
  8. 8.0 8.1 Incubator Updates
  9. https://www.duolingo.com/comment/1627314$comment_id=1658898
  10. Staff comment on "First two courses from the Incubator are now out of beta!"
  11. How does a course graduate from beta?