List

NACLO Problems and Solutions

A linguistics and computational linguistics contest for secondary students in the USA and Canada, first held in 2007: an open first round sat at sites across both countries, and an invitational second round from which the US team for the IOL is chosen. Both rounds of every year are here, each problem with its own solution.

2026

USA and Canada

Round 1
Problems9 problemsFull paperAll solutions
  • 1The Horse Before The CartProblemSolution
  • 2Game: Set MatchProblemSolution
  • 3Sheninagans in KogiProblemSolution
  • 4Witsuwit’en Word SaladProblemSolution
  • 5A Typical ProblemProblemSolution
  • 6Meowing in MāoriProblemSolution
  • 7A Manam FamilyProblemSolution
  • 8A Tale of Three ScriptsProblemSolution
  • 9Up In FlamesProblemSolution

2025 materialsRound 2 results

2025

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1Fox out of the BoxProblemSolution
  • 2Swidden in Plain SightProblemSolution
  • 3Color Me ConfusedProblemSolution
  • 4Let’s Pivot!ProblemSolution
  • 5Around the World in ArmenianProblemSolution
  • 6Not Quite RightProblemSolution
  • 7The Little Dog That Could ReadProblemSolution
  • 8There Is Another HandProblemSolution
Round 2
Problems8 problemsFull paperAll solutions
  • 9A Handheld TabletProblemSolution
  • 10Nganasan IdolProblemSolution
  • 11Going By the NumbersProblemSolution
  • 12Whistle While You WorkProblemSolution
  • 13Relative ClausesProblemSolution
  • 14Something That Is SolvedProblemSolution
  • 15I Speak, Therefore I AmProblemSolution
  • 16The Greatest Thing Since Boiled BreadfruitProblemSolution

2024 materialsRound 2 results

2024

USA and Canada

Round 1
Problems8 problemsProblemsSolutions
  • 1Holy Roman Shorthandnot published
  • 2Finding Your Place in Warlpirinot published
  • 3Happy Birthday!not published
  • 4Generally Speakingnot published
  • 5Japanese From Afarnot published
  • 6Paiwan in Progressnot published
  • 7At a Loss for Wordsnot published
  • 8Evidentially, My Dear Tariananot published
Round 2
Problems10 problemsProblems
  • 9In the Scottish Highlandsnot published
  • 10aLLMost, but not quitenot published
  • 11I Know a Szpőtnot published
  • 12Some Horses of Their Fathernot published
  • 13Maonan Animalsnot published
  • 14A Trip Down Memory Lanenot published
  • 15Allow Me To Demonstratenot published
  • 16Stressed Out in Kilivilanot published
  • 17From 1 to 276not published
  • 18Follow the Rulesnot published

2023 materialsRound 2 results

2023

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1The Way We WereProblemSolution
  • 2Don't StressProblemSolution
  • 3VloxesProblemSolution
  • 4For the Sake of Their HouseProblemSolution
  • 5Bengalese Finch SongProblemSolution
  • 6A Calabash CalculationProblemSolution
  • 7Feathers of the Roseate SpoonbillProblemSolution
  • 8My Grandmother and IProblemSolution
Round 2
Problems9 problemsFull paperAll solutions
  • 9Show That One for the PeopleProblemSolution
  • 10Marshallese PhonolojiProblemSolution
  • 11Wordnet BattleshipProblemSolution
  • 12Camp Not-So-PleasanthillProblemSolution
  • 13Tongue Tied in ChukchiProblemSolution
  • 14A Saharan SensationProblemSolution
  • 15Tone's PuzzleProblemSolution
  • 16Counting in RoonProblemSolution
  • 17What to WearProblemSolution

2022

USA and Canada

Round 1
Problems9 problemsFull paperAll solutions
  • 1Lines in the SandProblemSolution
  • 2Who Saw the Bear?ProblemSolution
  • 3To Make a Long Story ShortProblemSolution
  • 4Real NumbersProblemSolution
  • 5Sleeping in the ShadeProblemSolution
  • 6Splash to SaveProblemSolution
  • 7Out of OrderProblemSolution
  • 8From Soup to NutsProblemSolution
  • 9A Cornish ConundrumProblemSolution
Round 2
Problems9 problemsFull paperAll solutions
  • 10Sounds FishyProblemSolution
  • 11A Tough Word to SwallowProblemSolution
  • 12Stopping for a SpellProblemSolution
  • 13A Splitting DisagreementProblemSolution
  • 14Pseudorandom NumbersProblemSolution
  • 15Seeing the FutureProblemSolution
  • 16YumologyProblemSolution
  • 17Relatively SpeakingProblemSolution
  • 18I Stop Being Afraid of This ProblemProblemSolution

2021

USA and Canada

Round 1
Problems9 problemsFull paperAll solutions
  • 1The Tortoise and the RabbitProblemSolution
  • 2Junk Mail: Letters We Don't NeedProblemSolution
  • 3Versatile VerbProblemSolution
  • 4Made You Look!ProblemSolution
  • 5The Script of Your DreamsProblemSolution
  • 6The Wiles of ReptilesProblemSolution
  • 7The Skates of WrathProblemSolution
  • 8SequiturProblemSolution
  • 9Non SequiturProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 10A Vintage Sound SystemProblemSolution
  • 11Putting a Place to a NameProblemSolution
  • 12Is This Problem Intelligible?ProblemSolution
  • 13The Speech Has No EndProblemSolution
  • 14Do I Care about Duikers?ProblemSolution
  • 15Cameroonian CompoundsProblemSolution
  • 16Family TiesProblemSolution
  • 17A Stress TestProblemSolution
  • 18GloVe CompartmentProblemSolution
  • 19Peace OnlyProblemSolution

2020

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1Let That Mongo!ProblemSolution
  • 2A Cat in a HatProblemSolution
  • 3Set in StoneProblemSolution
  • 4Pay AttentionProblemSolution
  • 5Breton NumbersProblemSolution
  • 6Coming into FocusProblemSolution
  • 7Password ConfusionProblemSolution
  • 8The Idalion TabletProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9Kãa, Kai, and KhaiProblemSolution
  • 10You Made Me SeeProblemSolution
  • 11The Pimpled ToadProblemSolution
  • 12Shiva SutrasProblemSolution
  • 13Adjupectiheaval!ProblemSolution
  • 14You Can’t Handle the TruthProblemSolution
  • 15We’re Counting on YorubaProblemSolution
  • 16Doubling Up on NakanaiProblemSolution
  • 17Cut to the ChaseProblemSolution
  • 18The Obviative SolutionProblemSolution

2019

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1MalteaserProblemSolution
  • 2You Speak Ndebele, Don't You?ProblemSolution
  • 3Here is One HandProblemSolution
  • 4Predicate EtiquetteProblemSolution
  • 5Hate It or LopitProblemSolution
  • 6HarmongoliaProblemSolution
  • 7Break it Down!ProblemSolution
  • 8Can you know/Hanunó'oProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9The Afrihili Word MachineProblemSolution
  • 10Polish These Nouns!ProblemSolution
  • 11Two Róngs Don't Make a RightProblemSolution
  • 12We Were Born to Solve This ProblemProblemSolution
  • 13Colorless Green Concepts Scripting FuriouslyProblemSolution
  • 14Fun With Witsuwit'enProblemSolution
  • 15Infer a SurpriseProblemSolution
  • 16Do You Hear the Master's MoonProblemSolution
  • 17A Tale of Kieu-pletsProblemSolution
  • 18Disambiguate This!ProblemSolution

2018

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1At Ease in GilberteseProblemSolution
  • 2The Pame GameProblemSolution
  • 3All Roads Lead to TiranaProblemSolution
  • 4Intergalactic GrammarsProblemSolution
  • 5Parties in PalauanProblemSolution
  • 6A Match Made in VietnamProblemSolution
  • 7By the Same TokenProblemSolution
  • 8N'ko, M'kayProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9A Menya PuzzleProblemSolution
  • 10It's True: The Truth About Chalcatongo MixtecProblemSolution
  • 11Sri Lankan NamesProblemSolution
  • 12Peeled Potato Act with AnnieProblemSolution
  • 13Quests and Requests in NivkhProblemSolution
  • 14You've Got This: Fijian OwnershipProblemSolution
  • 15To Know or Not to Know Literary TamilProblemSolution
  • 16I Know What I SawProblemSolution
  • 17Better Left UnsaidProblemSolution
  • 18A Make-Shift CodeProblemSolution

2017

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1A Little TshilubaProblemSolution
  • 2Pho BarProblemSolution
  • 3LolwutProblemSolution
  • 4Let's Roll!ProblemSolution
  • 5On the Right TrackProblemSolution
  • 6Transition(al) NumbersProblemSolution
  • 7Magik Yup’ikProblemSolution
  • 8Nothing but (Net)worksProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9Basque TasqueProblemSolution
  • 10The Norwegian Problem / A Norwegian Problem / Norwegian Problems / The Norwegian Problems?ProblemSolution
  • 11Sentences that go on and on and on and onProblemSolution
  • 12The Goat, the Mother, and the WardrobeProblemSolution
  • 13It will be you who solves this problem!ProblemSolution
  • 14To Be DeterminedProblemSolution
  • 15Common SenseProblemSolution
  • 16Do you see what I see?ProblemSolution
  • 17Pluses and MinusesProblemSolution
  • 18Text-o-maticProblemSolution

2016

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1Tangled up in NotsProblemSolution
  • 2DAWG BreedsProblemSolution
  • 3The Curious Case of EstonianProblemSolution
  • 4That's an OrderProblemSolution
  • 5Be There, or be SquaredProblemSolution
  • 6Take one Tablet and Call me in the MorningProblemSolution
  • 7Signs from AboveProblemSolution
  • 8Fan FictionProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9Deriving EnjoymentProblemSolution
  • 10Get EdumacatedProblemSolution
  • 11Kings, Queens, and CountsProblemSolution
  • 12The Short Hand of the LawProblemSolution
  • 13Sound JudgmentsProblemSolution
  • 14What Happened at the Chess Tournament?ProblemSolution
  • 15Don't Sell the HouseProblemSolution
  • 16A matter of Horn clausesProblemSolution
  • 17A cup of JavaneseProblemSolution
  • 18Changing the SubjectProblemSolution

2015

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1The Big Dog and the Young ManProblemSolution
  • 2Delphi has the AnswersProblemSolution
  • 3Aymara RulesProblemSolution
  • 4Elder Futhark RunesProblemSolution
  • 5Use the ForceProblemSolution
  • 6My Friend Nomura from OsakaProblemSolution
  • 7Zoink!ProblemSolution
  • 8Phaasaa and PhaasaaProblemSolution
Round 2
Problems8 problemsFull paperAll solutions
  • 9Old EnglishProblemSolution
  • 10Georgian Transitive VerbsProblemSolution
  • 11The Dualization GameProblemSolution
  • 12Easy-Peasy-MalagasyProblemSolution
  • 13Minimum Spelling TreesProblemSolution
  • 14MaxakaliProblemSolution
  • 15Do-This-Do-ThatProblemSolution
  • 16The Old Man the BoatsProblemSolution

2014

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1What's the Time in Tallinn?ProblemSolution
  • 2Māori LoanwordsProblemSolution
  • 3Levenshtein's Fine SignsProblemSolution
  • 4Wheel of Fortune CookiesProblemSolution
  • 5Visible SpeechProblemSolution
  • 6LontaraProblemSolution
  • 7Cameroon Pidgin EnglishProblemSolution
  • 8Bertrand and RussellProblemSolution
Round 2
Problems9 problemsFull paperAll solutions
  • 9To play or not to playProblemSolution
  • 10LexicondensedProblemSolution
  • 11Don't be Ukhrul to a Liver that's TrueProblemSolution
  • 12Transducing RunesProblemSolution
  • 13Come to IstanbulProblemSolution
  • 14Hungarian RocksProblemSolution
  • 15CcgProblemSolution
  • 16Combining Categories in Tok PisinProblemSolution
  • 17Learning YidinyProblemSolution

2013

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1Intuitive InuitProblemSolution
  • 2A Case of PaliProblemSolution
  • 3The Heads and Tails of HuffmanProblemSolution
  • 4Kwak'wala Word SearchProblemSolution
  • 5Shaw BusinessProblemSolution
  • 6Grammar Rules!ProblemSolution
  • 7Phoenician FunProblemSolution
  • 8TwodeeProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9BejaProblemSolution
  • 10Stockholms TunnelbanaProblemSolution
  • 11Putting the Books in OrderProblemSolution
  • 12YesbotProblemSolution
  • 13Playing the Cognate GameProblemSolution
  • 14A Tree by Any Other NameProblemSolution
  • 15Warlpiri Kinship GroupsProblemSolution
  • 16Deer FatherProblemSolution
  • 17Grice's Grifter GadgetsProblemSolution
  • 18Poles ApartProblemSolution

2012

USA and Canada

Round 1
Problems8 problemsFull paperAll solutions
  • 1Cat and Mouse StoryProblemSolution
  • 2Learn Yolmo with pleasureProblemSolution
  • 3Interstellar First ContactProblemSolution
  • 4All in the FamilyProblemSolution
  • 5Traevölörs FreisbukProblemSolution
  • 6Crocodile BardiProblemSolution
  • 7Haitian CreoleProblemSolution
  • 8Waorani NumbersProblemSolution
Round 2
Problems10 problemsFull paperAll solutions
  • 9The silence of the goatsProblemSolution
  • 10Ik heb voorspeldProblemSolution
  • 11A fox among the hProblemSolution
  • 12Who is good?ProblemSolution
  • 13The Deschamps CodiceProblemSolution
  • 14WaanyiProblemSolution
  • 15The Little Engine that Could...ReadProblemSolution
  • 16Jeg kan tælleProblemSolution
  • 17100 SurnamesProblemSolution
  • 18One, Two, TreeProblemSolution

2011

USA and Canada

Round 1
Problems7 problemsFull paperAll solutions
  • 1Running on MTProblemSolution
  • 2Mix Up on the FarmProblemSolution
  • 3The War of the DotsProblemSolution
  • 4Double or Quit in Caterpillar CountryProblemSolution
  • 5BrokEnglish!ProblemSolution
  • 6Tiger TaleProblemSolution
  • 7Ulwa PossessivesProblemSolution
Round 2
Problems7 problemsFull paperAll solutions
  • 8Counting in IrishProblemSolution
  • 9A Large Spoon is EnoughProblemSolution
  • 10Axolotl in the WaterProblemSolution
  • 11A Script for the NdyukaProblemSolution
  • 12Swallow the SaltProblemSolution
  • 13Word SaladProblemSolution
  • 14Stopping and Flapping in WarlpiriProblemSolution

2010

USA and Canada

Round 1
Problems7 problemsFull paperAll solutions
  • 1Gelda's House of GelbelgargProblemSolution
  • 2Say It in AbmaProblemSolution
  • 3Lost in YerevanProblemSolution
  • 4Huevos y PimientosProblemSolution
  • 5Texting, Texting, One Two ThreeProblemSolution
  • 6Türkış DelıtProblemSolution
  • 7Tangkhul TangleProblemSolution
Round 2
Problems9 problemsFull paper
  • 8Ardhay UzzlepayProblemSolution
  • 9Dogs and cats on treesProblemSolution
  • 10Plains CreeProblemSolution
  • 11F u cn rd thsProblemSolution
  • 12Real MoneyProblemSolution
  • 13No smoke without fireProblemSolution
  • 14Tale of KieuProblemSolution
  • 15Possessed in VanuatuProblemSolution
  • 16KhipuProblemSolution

2009

USA and Canada

Round 1
Problems6 problemsFull paperAll solutions
Round 2
Problems7 problemsFull paper

2008

USA and Canada

Round 1
Problems5 problemsFull paperAll solutions
  • 1Of monkeys and childrenProblemSolution
  • 2Springing up babyProblemSolution
  • 3Reach for the topProblemSolution
  • 4Spare the RodProblemSolution
  • 5A Fish StoryProblemSolution
Round 2
Problems7 problemsFull paperAll solutions
  • 6FakepapershelfmakerProblemSolution
  • 7Manam, I'm AnamProblemSolution
  • 8Thorny StemsProblemSolution
  • 9aw-TOM-uh-tuhProblemSolution
  • 10The Curragh of KildareProblemSolution
  • 11Tzolk'inProblemSolution
  • 12The Whole SpectrumProblemSolution

2007

USA and Canada

Problems8 problemsFull paperAll solutions
  • 1We are all molistic in a wayProblemSolution
  • 2Pooh's encyclipediaProblemSolution
  • 3A donkey in every houseProblemSolution
  • 4HmongProblemSolution
  • 5Better sorry than shunkProblemSolution
  • 6The lost tramProblemSolution
  • 7Rewrite me baddProblemSolution
  • 8This problem is pretty // easyProblemSolution