What is NACLO?

NACLO is a contest in which high-school students solve linguistic puzzles. In solving these puzzles, students learn about the diversity and consistency of language, while exercising logic skills. No prior knowledge of linguistics or second languages is necessary. Professionals in linguistics, computational linguistics and language technologies use dozens of languages to create engaging problems that represent cutting edge issues in their fields. The competition has attracted top students to study and work in those same fields. It is truly an opportunity for young people to experience a taste of natural-language processing in the 21st century.


  • February 15, 2020Grading is over (with a few exceptions). See the results. If your score is missing or if you notice any other problem, please contact naclo20org@umich.edu asap.
  • February 10, 2020The list of submitted booklets is now available. If you don't see your number here, please contact naclo20org@umich.edu asap
  • January 23, 2019On-site registration is open now for the sites that allow walk-ins. The registration site will be closed for good after the end of the contest later today
  • January 22, 2019Regular registration ends today (January 22) at 3 PM EST (12 noon PST). It will reopen for walk-in registration tomorrow (January 23) morning and close again for good after the end of the contest. If you are a student, you can check if your site allows walk-ins. All participants have to register in order to compete.
  • December 1, 2019Announcement about the new name of this competition.
  • September 7, 2019Registration for 2020 has started.

    Student registrations are not carried over from one year to the next. If you are a student and had registered prior to September 15, you will need to register again from scratch.

    Site registrations (high school and university sites) are automatically copied from one year to the next.

  • August 12, 2019 The dates for the 2020 contest are January 23 (open round) and March 5, 2020 (invitational round).
  • The NACLO 2020 Student Handbook
  • The NACLO 2020 Coordinator Handbook
  • The NACLO 2020 Appendix

Please Donate

You can help support NACLO either by mailing a check or giving online. For more information on both, please see our donations page. We thank you for your support!


We're looking for new sites and problem contributors. Please contact us at naclo20org@umich.edu.