Koch Lesson 3: Add the Letter S

Why this step

S is three short elements — the bookend of SOS. In Koch it arrives after you already copy two dah letters and R. The job is to hear a burst of dits as one letter, not as “E E E.”

What to hear

S is a compact “dit-dit-dit.” M is “dah-dah.” They are opposites in duration and tone. If S smears into a single buzz, your audio is too fast relative to your attention; keep WPM, take a shorter session.

Drill

Active set: K, M, R, S. Copy SK as two letters when you are ready, but the module still quizzes one character at a time. Share the lesson-3 practice URL so someone else uses this exact set.

Letter groups you can type in the translator once the ear is warm: S, SK, RS, MS

Pitfall

People who learned SOS visually send S as three slow taps. Koch wants the three dits inside one letter-length at 20 WPM.