Adaptive Typing Practice: lessons built from your own weak keys

The mastery map

Every key sits in one of five tiers: mastered, reliable, improving, learning and needs review. A key moves up on clean, unhurried repetitions and slips back when it starts costing you time or accuracy again, so the map reflects your typing this week rather than your typing in general. It is the same map the kids world draws as an island chart and the adult world draws as a keyboard heatmap.

Keys are only half of it. The engine also tracks transitions, the letter pairs your hands have to move between, because a slow O and a slow L are a different problem from a slow O followed by an L. Pair timing is where most of the speed hiding in an intermediate typist actually is.

How a practice set gets built

1. Pick the targets. The two or three weakest keys, plus the slowest transitions that involve them.
2. Find real words. Targets are wrapped in genuine vocabulary rather than nonsense strings, so you practise the movement in the shape it takes in real writing.
3. Keep it honest. Sets are salted with keys you already own, so a session is not a wall of your worst letters and your accuracy has somewhere to stand.
4. Re-read and adjust. The set that follows is chosen from the data this one produced, not from a fixed schedule.

A coach that names the fix

Encouragement is easy to generate and worth very little. After every session Kip reads the actual numbers and says which keys, which transition, and what to do about it in the next three minutes. When you are ready to chase speed it says so. When you are not, it says that too, and explains why holding accuracy first gets you there faster.

What the engine is actually looking at

Two measurements drive everything: how long each key takes you, and how long each letter pair takes you. They are recorded separately because they fail separately. A key can be slow because the reach is unfamiliar, and a pair can be slow even when both of its keys are fast, because the join between them is where the hand has to reorganise.

Both are noisy at small samples, so a key is not treated as weak until it has been seen at least four times. Without that floor the practice set would rebuild itself around one bad afternoon, and you would spend a week drilling a letter you were never actually slow on.

Why frequency weighting matters

A slow, common transition costs you far more than a slow, rare one, so the two are not worth the same amount of practice. Weighting by how often a pattern actually occurs in English is what stops adaptive practice turning into a tour of your most exotic weaknesses while the pairs you meet in every third sentence stay slow.

It is also what keeps the material readable. Practice generated purely to maximise weak transitions drifts towards dense, unnatural strings that are unpleasant to type and nothing like real writing, so the generator is constrained to real words and real sentences with your weak patterns concentrated inside them.

What it cannot see

The engine measures what your hands produce, not how they produce it. Someone typing at 60 words per minute with two or three improvised finger assignments looks, from the outside, identical to someone typing correctly at 60, because the keystrokes and the timings are the same. Finger assignment is the one thing that has to be checked by a person, which is why the lessons teach it explicitly rather than leaving it to be inferred.