This section answers some questions about the course creation process.
Language Courses

What is the language Incubator?Edit

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?Edit

Languages such as Japanese and Chinese[2] have been planned[3][4][5] for considerable time but according to staff member, Gina Gotthilf, "the reason we don’t teach a lot of Asian languages is we are now sticking to languages that don’t require explaining a whole new alphabet"[6]. The choice of languages being added to the incubator depends on a lot of factors including Duolingo's internal knowledge of them[7][8].

How long does it take to make a course?Edit

On average it takes 3 months to create a beta course.[9]

When will a reverse course be added? Edit

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

How does Duolingo decide which course to add next?Edit

According to CEO Luis von Ahn:[10]

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? Edit

DL Incubator Course Application Options eng

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?Edit

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.[11] Much of an original course's content will also be used to create its "reverse course",[12] 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?Edit

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.[12]

What is the minimum number of contributors required?Edit

Duolingo will always require 2 qualified moderators per course[13].

What is a "beta" course?Edit

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)?Edit

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

How does a course graduate from beta?Edit

A course typically graduates from beta when the Duolingo team and the incubator contributors believe a course is stable[14] and receives less than 3 reports per 100 users.[15]


  1. Duolingo Launches Language Incubator (TechCrunch). Retrieved 2015-05-22.
  3. Reddit, IAmA scientist and startup CEO named Luis von Ahn., Luis von Ahn, July 11, 2012.
  4. Reddit, I am Luis von Ahn, the creator of reCAPTCHA, those squiggly characters all over the web, and the co-founder and CEO of DUOLINGO!, Luis von Ahn, November 20, 2014.
  6. "Gina gotthilf ", Duolingo staff (2015),
  7. "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"
  9. Duolingo UGC challenges
  10. Reddit, "IAm Luis von Ahn, co-founder and CEO of Duolingo. AMA.", Luis von Ahn, April 14, 2014.
  11. Incubator: Are you supposed to submit applications for both directions?
  12. 12.0 12.1 Incubator Updates
  14. Staff comment on "First two courses from the Incubator are now out of beta!"
  15. How does a course graduate from beta?