Practice Problems

We have many ways for you to practice for upcoming competitions:

To search problems or browse by venues, languages, etc., check out the NACLO problem database.

NACLO Online Practice

NACLO Online Practice is an interactive online system that allows you to practice with problems from previous competitions and have them automatically scored. Below is a list of problems that are included in this system. Click on a problem's title to be taken to that problem's page.

NACLO 2016 Problems

Name Solution Author
Tangled up in Nots Solution Bozhidar Bozhanov
DAWG Breeds Solution Patrick Littell
The Curious Case of Estonian Solution Praveen Venkataramana
That's an Order Solution Dorottya Demszky, Yiwei Luo, and Tom McCoy
Be There, or be Squared Solution Bill Huang
Take one Tablet and Call me in the Morning Solution Dorottya Demszky
Signs from Above Solution James Hyett
Fan Fiction Solution Ben King
Deriving Enjoyment Solution Harold Somers and Simona Klemenčič
Get Edumacated Solution Patrick Littell
Kings, Queens, and Counts Solution Tom McCoy
The Short Hand of the Law Solution Dragomir Radev and Patrick Littell
Sound Judgments Solution Ollie Sayeed
What Happened at the Chess Tournament? Solution Vica Papp
Don't Sell the House Solution Alex Wade
A matter of Horn clauses Solution Josh Falk
A cup of Javanese Solution Tae Hun Lee
Changing the Subject Solution Harold Somers
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2015 Problems

Name Solution Author
The Big Dog and the Young Man Solution Mike Swan
Delphi has the Answers Solution Bozhidar Bozhanov
Aymara Rules Solution Josh Falk
Elder Futhark Runes Solution Catherine Sheard
Use the Force Solution Jonathan May
My Friend Nomura from Osaka Solution Harold Somers
Zoink! Solution Dragomir Radev, Christiane Fellbaum, and Jonathan May
Phaasaa and Phaasaa Solution Alex Wade
Old English Solution Graeme Trousdale
Georgian Transitive Verbs Solution Dorottya Demszky and Adam Hesterberg
The Dualization Game Solution Daniel Lovsted
Easy-Peasy-Malagasy Solution Tom McCoy
Minimum Spelling Trees Solution John de Nero
Maxakali Solution Alexander Wade and Pat Littell
Do-This-Do-That Solution David Mortensen
The Old Man the Boats Solution Emily Bender
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2014 Problems

Name Solution Author
What's the Time in Tallinn? Solution Babette Newsome
Māori Loanwords Solution Patrick Littell
Levenshtein's Fine Signs Solution Blake Allen and Patrick Littell
Wheel of Fortune Cookies Solution Patrick Littell
Visible Speech Solution Natalie Weber and Patrick Littell
Lontara Solution Chelsea Voss
Cameroon Pidgin English Solution Aleka Blackwell
Bertrand and Russell Solution Ben King
To play or not to play Solution Catherine Sheard
Lexicondensed Solution Tom McCoy
Don't be Ukhrul to a Liver that's True Solution David Mortensen
Transducing Runes Solution Jordan Boyd-Graber
Come to Istanbul Solution David Palfreyman
Hungarian Rocks Solution Adam Hesterberg
CCG Solution Jonathan Kummerfeld, Aleka Blackwell, and Patrick Littell
Combining Categories in Tok Pisin Solution Jonathan Kummerfeld, Aleka Blackwell, and Patrick Littell
Learning Yidiny Solution Mary Laughren
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2013 Problems

Name Solution Author
Intuitive Inuit Solution Harold Somers
A Case of Pali Solution Babette Verhoeven
The Heads and Tails of Huffman Solution John DeNero
Kwak'wala Word Search Solution Patrick Littell
Shaw Business Solution Babette Verhoeven
Grammar Rules! Solution Andrea Schalley and Patrick Littell
Phoenician Fun Solution Harold Somers
Twodee Solution Jason Eisner
Beja Solution Richard Hudson
Stockholms Tunnelbana Solution Patrick Littell
Putting the Books in Order Solution Dragomir Radev
Yesbot Solution Patrick Littell
Playing the Cognate Game Solution Catherine Sheard
A Tree by Any Other Name Solution John DeNero
Warlpiri Kinship Groups Solution Alan Chang
Deer Father Solution Patrick Littell
Grice's Grifter Gadgets Solution Jordan Boyd-Graber
Poles Apart Solution Dragomir Radev
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2012 Problems

Name Solution Author
Cat and Mouse Story Solution Patrick Littell
Learn Yolmo with pleasure Solution Lauren Gawne
Interstellar First Contact Solution Simon Zwarts, based on work by Kevin Knight
All in the Family Solution Dragomir Radev
Traevölörs Freisbuk Solution Patrick Littell
Crocodile Bardi Solution Catherine Sheard
Haitian Creole Solution Ivaylo Youmerski
Waorani Numbers Solution Dragomir Radev
The silence of the goats Solution Alexey Pegushev
Ik heb voorspeld Solution Dick Hudson
A fox among the h Solution Pat Littell
Who is good? Solution Dick Hudson
The Deschamps Codice Solution Alexander Piperski
Waanyi Solution Mary Laughren
The Little Engine that Could...Read Solution Pat Littell and James Pustejovsky
Jeg kan tælle Solution Harold Somers
100 Surnames Solution Pat Littell
One, Two, Tree Solution Noah Smith, Kevin Gimbel, and Jason Eisner
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2011 Problems

Name Solution Author
Running on MT Solution Harold Somers
Mix Up on the Farm Solution Lori Levin
The War of the Dots Solution Patrick Littell
Double or Quit in Caterpillar Country Solution Mark Dras
BrokEnglish! Solution Patrick Littell
Tiger Tale Solution Dragomir Radev
Ulwa Possessives Solution Richard Sproat
Counting in Irish Solution Tom Payne
A Large Spoon is Enough Solution Harold Somers
Axolotl in the Water Solution John Berman
A Script for the Ndyuka Solution Patrick Littell
Swallow the Salt Solution Bozhidar Bozhanov
Word Salad Solution Eric Breck
Stopping and Flapping in Warlpiri Solution Mary Laughren
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2010 Problems

Name Solution Author
Gelda's House of Gelbelgarg Solution Patrick Littell
Say It in Abma Solution Cindy Schneider
Lost in Yerevan Solution Dragomir R. Radev
Huevos y Pimientos Solution Dragomir R. Radev
Texting, Texting, One Two Three Solution Patrick Littell
Türkış Delıt Solution Bozhidar Bozhanov
Tangkhul Tangle Solution David Mortensen
Ardhay Uzzlepay Solution John Henderson with the assistance of Sophie Crouch, University of Western Australia. Based on Crouch (2008, 2009) and data from the MPI EVA Minangkabau corpus
Dogs and cats on trees Solution Emily Bender
Plains Cree Solution Patrick Littell and Julia Workman
F u cn rd ths Solution Richard Sproat
Real Money Solution Patrick Littell
No smoke without fire Solution Aleka Blackwell
Tale of Kieu Solution David Mortensen and Patrick Littell
Possessed in Vanuatu Solution Jane Simpson, University of Sydney and Jeremy Hammond, Max Planck Institute for Psycholinguistics
Khipu Solution Patrick Littell and Erin Donnelly
All Round 1 Problems All Solutions
All Round 2 Problems

NACLO 2009 Problems

Name Solution Author
Tenji karaoke Solution Patrick Littell
Nok-nok! Solution Eugene Fink
Letters for Cuzco Solution Patrick Littell
You will be laughing Solution Bozhidar Bozhanov
Summer Eyes Solution Dragomir Radev and Adam Hesterberg
Help my camera! Solution Emily Bender
Sk8 Parsr Solution Patrick Littell
Linear Combinations Solution Richard Sproat
Easy Pieces Solution Todor Tchervenkov
Hypo-Hmong-driac Solution David Mortensen
The gerbil arrived Solution Bozhidar Bozhanov
Yak, Du, Dray Solution Dragomir Radev
Orwellspeak Solution Jason Eisner
All Round 1 Problems All Solutions
All Round 2 Problems

NACLO 2008 Problems

Name Solution Author
Of monkeys and children Solution Ronnie Sim and Thomas Payne
Springing up baby Solution Ankit Srivastava and Emily Bender
Reach for the top Solution Patrick Littell
Spare the Rod Solution Dragomir Radev
A Fish Story Solution Patrick Littell
Fakepapershelfmaker Solution Willie Costello
Manam, I'm Anam Solution Patrick Littell
Thorny Stems Solution Eric Breck
aw-TOM-uh-tuh Solution Patrick Littell
The Curragh of Kildare Solution Todor Tchervenkov
Tzolk'in Solution Patrick Littell and Erin Donnelly
The Whole Spectrum Solution Adam Hesterberg
All Round 1 Problems All Round 1 Solutions
All Round 2 Problems All Round 2 Solutions

NACLO 2007 Problems

Name Solution Author
We are all molistic in a way Solution Dragomir Radev
Pooh's encyclopedia Solution Eugene Fink
A donkey in every house Solution Todor Tchervenkov
Hmong Solution Ivan Derzhanski
Better sorry than shunk Solution Jason Eisner and Roy Tromble
The lost tram Solution Boris Iomdin
Rewrite me badd Solution Patrick Littell and David Mortensen
This problem is pretty // easy Solution Dragomir Radev
All Problems All Solutions

Student Contributed Problems

Name Solution Author
Hebrew Morris Alper
Japanese Morris Alper
Tamil Solution Anand Natarajan
Welsh Solution Anand Natarajan
Yers Solutions Anand Natarajan

Sample Practice Problems

Name Solution Author
Agta Solution Tom Payne
Alliteration Solution Jason Eisner and Roy Tromble
Ambiguous Solution Emily Bender
Amharic Solution Yekaterina Iassinskaya
Anishinaabemowin Solution Patrick Littell
Cognates Solution Dragomir Radev
Finite-state transducers Solution Richard Sproat
Finite-state transducers Solution Tom Payne
Handwriting recognition Solution Tom Payne
Hawaiian Solution V. Belikov
Hieroglyphics Solution Tom Payne
Luvian Solution A. Zhurinsky
Maa Solution Doris L. Payne
Magicsquare Solution John Blatz
Phonebook Solution Jason Eisner and Roy Tromble
Scrabble Solution Roy Tromble
Tamil Solution Eric Pederson
Transformations Solution Lori Levin
Walrus Solution Boris Iomdin
Weasel Solution John Blatz and Jason Eisner

Problems from Other Sources