Linguistics

NACLO 2025

Brown University will be hosting the 2025 North American Computational Linguistics Open competition on January 23rd, 2025. High school and middle school students will be asked to use their logic and reasoning skills to solve a variety of linguistic puzzles. No background in languages is necessary, and all students with an interest are encouraged to compete.

Breadcrumb

What is NACLO?

NACLO stands for the North American Computational Linguistics Open. It is a competition for students in high school or younger, where participants are asked to solve a variety of linguistics problems. Competitors do not need to have a background in computational linguistics or language to enter, but should be confident in their reasoning, logic and analytical skills.

Those who do well in the Open Round will then be asked to move on to the Invitational Round. Participants who exceed in the second round may be asked to join the United States team and compete internationally.

How do I register for NACLO?

Students can register for the first round of the competition here. Registration is free.

When is it?

The Open Round will be held on Brown University's campus on January 23rd, 2025 from 10am-1pm, with registration opening at 9am. 

Where can I learn more?

More information about NACLO can be found on their website as well as in their handbook.

Sample Problems

NACLO provides sample questions for students to practice with on their website. Below is an example of a problem that could be given during the competition.

 

WHEEL OF FORTUNE COOKIES (2014)

A popular category on the game show Wheel of Fortune is the “Before and After” clue, in which contestants have to guess the middle word in a phrase like “CANDY BAR CHART” or “CHESHIRE CAT FOOD”. The fun of these phrases lies in the fact that even though each adjacent pair of words is a familiar combination, the resulting chain is often absurd. 

D1. Below, we’ve used Google Ngram Viewer to construct chains of nouns where the 2-word co-occurrence frequency is very high, but the 3-word (and 4- and 5-…) frequency is extremely low, like STORM CLOUD COVER LETTER. For each noun in the chain, we just chose the noun that most frequently followed it in Google’s enormous collection of books: STORM was most frequently followed by CLOUD, CLOUD was most frequently followed by COVER, etc. 

Can you work out the intermediate words in the following chains? Each blank represents a letter, and as a hint, blanks with the same number under them represent the same letter. Remember that we want the most common 2-word combination that starts with the given word, not just any 2-word combination. 

CREDIT __ __ __ _1_ GAME 
ICE __ __ __ __ _2_ CHEESE 
COUCH __ _3_ __ __ __ __ CHIP
BOWLING __ _4_ __ _5_ __    __ _6_ __ FOOD 
BEACH _7_ _8_ __ __ __    __ _9_ __ _5_ __ __ WARRANT 
FLOWER _10_ __ _1_    _9_ __ _11_ __    __ __ _3_ __ TEMPERATURE 
SPACE __ _7_ __ __ __ _4_ __    _10_ _8_ __    _11_ __ __ __ _12_ __ _13_ WAGON 
COWBOY __ __ __ _14_    __ __ _2_ __    __ _12_ __ __    __ __ __ _6_ __ _14_ __ __ _13_ __ STORE

Fill out a table with the letters that correspond to each number above.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 

D2. Below, invent your own three-word “Before and After” chains. Each pair of words should be much more common than you'd expect from the frequencies of its individual words, but the whole triplet should be rare. You don’t have to stick just to nouns; you can use any words. 
1. _________________ _________________ ______________
2. _________________ _________________ ______________
3. _________________ _________________ ______________