I, M, S, O: Building on Basics
Learn four more essential letters with symmetric patterns. These letters form the famous SOS distress signal!
Learn the Characters
Click on each card to hear the sound. A dot (·) is a short beep, a dash (−) is three times longer.
The letter I is two dots (··). Think of it as "E doubled" - it's the second most common vowel!
The letter M is two dashes (−−). It's like "T doubled" - symmetric and easy to remember.
The letter S is three dots (···). The famous SOS signal starts with this letter!
The letter O is three dashes (−−−). Combined with S, it forms the universal distress signal SOS.
💡 Pattern Recognition
• Doubling pattern: I (··) is E doubled, M (−−) is T doubled.
• Tripling pattern: S (···) is three dots, O (−−−) is three dashes.
• SOS: The most famous Morse code signal: ··· −−− ···
🆘 The Famous SOS Signal
With S and O, you can now send the universal distress signal!
Listening Practice
Listen to the Morse code and identify which letter you hear. This trains your ear to recognize the patterns.
Listen and identify the letter:
Typing Practice
Type the Morse code for the letter shown. Use . for dot and - for dash.
Type the Morse code for:
Quick Quiz
Test your knowledge! Answer these questions to complete the lesson.
What is the Morse code for I?