Language is compositional. It is a set of rules that work for units and sub-units that emerge into a form of communication, and since we all speak at least one language I believe it is to some degree intuitional how to reverse engineer it. Linguistics is fun!
Also: to solve a lot of interesting linguistics olympiad problems you don't have to have any field-specific knowledge at all, and you can solve most of them using just common sense — which is ~rare for international competitions.
On this page there are gamified problems from the International Linguistics Olympiad (IOL) and the International Linguistics Challenge (ILC), plus a few hand-built script-decipher pages. Each card has a scratchpad and a stopwatch against an olympiad-pace target; the rosetta and decipher problems also let you click a word or letter to light up every occurrence. The IOL cards run 2003 – 2023 (no 2020 — cancelled); for a year-by-year overview see the IOL browser.
Sources: 73 individual-contest problems from the International Linguistics Olympiad (IOL, 2003 – 2023, no 2020) and 5 ILC 2025 puzzles, plus a few hand-built script-decipher pages (Georgian, Irish). Every problem is answer-keyed and graded in-page — the IOL and ILC sets ship with full reference answers.