North American Computational Linguistics Open (NACLO), the route to IOL

No — this is the single most common misconception about NACLO. The official materials state that no background in linguistics, computer science, programming or foreign languages is required. Every problem is self-contained: students get a short sample of an unfamiliar language, work out its rules by logic, and apply them. Students with zero background regularly reach the Invitational Round in their first year.

NACLO is free for every eligible student, and host sites are not permitted to charge a participation fee. But it is a pen-and-paper contest taken in person at a registered university or high school site — there is no general online option. Virtual proctoring is a narrow exception, mainly for homeschooled students with no site within reach.

Registration opens October 5, 2026. The three-hour Open Round is on January 28, 2027 — Irvine students sit it at 9:00 am Pacific — and the four-hour Invitational Round is on March 18, 2027, starting at 9:00 am local time. Both rounds are pen and paper: no dictionaries, no notes and no electronic devices of any kind.

NACLO does not publish a fixed cutoff. It says only that high scorers in the Open Round are invited to the Invitational Round; invitations are limited and the effective threshold shifts each year with the field. The scoring rules help: there is no penalty for wrong answers and partial credit is given for partial reasoning, so write down any pattern you spot rather than leaving a problem blank.

Selection is based on the Invitational Round: the top four or eight US scorers who meet IOL eligibility rules form the national team, and up to four more high scorers may be invited as a second US team. Team members train weekly online from early May to mid-July. IOL 2027 runs July 21-28, 2027 in Bangkok, Thailand, with both individual and team contests.

You must sit NACLO in person at a registered site, either a university site or a high school site. The list is published on the official site each fall, and Southern California universities have hosted sites in past years. If nearby seats are tight, a teacher or librarian can apply to register your own school as a site. Lock this in as soon as registration opens in October.

Yes. The Open Round is open to middle and high school students; NACLO targets ages 13-18 and younger students may take part with parental permission. In middle school the sensible goal is familiarity with the problem types and reasoning practice, not advancement. The cycle repeats every year, so a student can compete annually and aim at the Invitational Round and the national team once in high school.

Preparation means the official Practice Problems archive of 300-plus past problems. Work through them by type (translation, numerals, writing systems, phonology, computational), under strict timing with pen and paper only, and review the official solution for the reasoning chain rather than just the answer. The section above lists which Irvine public high school already has a linguistics club offering peer practice; a student whose school has no similar group can prepare individually with the same archive, or use EDUBUS's small-group linguistics reasoning sessions in Irvine as a supplement. On applications: reaching the Invitational Round is a genuine national distinction, and making the US IOL team is rarer still. Both read strongly for linguistics, cognitive science, CS and AI.