rain
Jei ne staigus lietus, mes būtume pasiekę viršūnę iki vakaro.
If it had not been for the sudden rain, we would have reached the summit by evening.
The spellings this word turns up in. There are 14 of them.
Memory lets a word go along a curve. Spaced repetition puts the next review just before the word slips, so every repeat buys more time than the one before it.
Seven cases, no shared vocabulary and a stress mark nobody writes down. What is genuinely hard about Lithuanian for an English speaker, what is easier than advertised, and the order that works.
Verba sends a short dictation every morning and brings the word back exactly when it starts to fade.