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Fundamentals

Speech Technique

Good phraseology said badly is bad phraseology. The radio doesn't forgive haste — it rewards those who speak a little slower than they think necessary.

5 min read
ICAO Doc 9432 · Chapter 2
Stefano Dias, ATCO

The unwritten rules of radio voice

ICAO Doc 9432 codifies the phraseology, but says almost nothing about the voice. Yet, after listening to frequencies for a few hours, you notice that immediately-understood pilots all share the same vocal characteristics. There are five, and they're trainable.

1. Moderate cadence, sharp pauses

Ideal speed is about 100 words per minute — roughly the pace of a professional radio journalist. You don't rush, you don't drag. Practical rule: read your call mentally before transmitting, and maintain that same cadence.

Between "logical blocks", leave a micro-pause. "Lugano Tower / HB-PMR / ready for departure runway 19 / with information Charlie." The four slashes are 0.3-second pauses. They give the listener time to "save to memory" the previous information before processing the next.

2. Constant, medium-low volume

The headset microphone is designed to be used 2-3 cm from your mouth. Farther away you lose the lower vocal range; closer and the "pop" on P/B consonants distorts. Normal conversational volume, not shouted.

Shouting on the radio is useless — worse, it degrades the signal. The transmitter audio compressor cuts everything above a certain threshold. A shouted voice arrives at the controller distorted and clipped.

3. Neutral but not monotone

The flat robotic voice is just as hard to listen to as the panicked one. Keep your intonation slightly flatter than normal, but not 100% flat. Small tonal variations help the ear distinguish similar words.

4. Pronounce every syllable, including the final ones

In English we tend to swallow endings. "Lugano Towe..." instead of "Lugano Tower". "...for departur..." instead of "...for departure". On the radio, the final syllables matter most because they carry the unit of meaning. A clean final "r" on "Tower" is the difference between being understood and being asked to repeat.

5. Breathe before, not during

Public speaking professionals know it: breath should be taken before the sentence, not in the middle. On the radio it's even more true. Press PTT, take a half breath, speak. If you're out of breath halfway through, release PTT, breathe, try again — don't keep forcing with a strangled voice.

The six most common errors

I recognize them every day on frequency. They're universal.

Frequent errors

1. Pressing PTT and starting to speak in the same instant. Result: the first syllable is always lost. Press PTT, wait 0.3 seconds, then speak.

2. Releasing PTT too early. The last word gets cut off. Wait 0.3 seconds after finishing, then release.

3. Filler words. "Uh", "okay", "so", "like", "basically". Every filler is radio time stolen from others. If you need to think, release PTT and rethink.

4. Voice eaten by the mic. Microphone too close, or positioned under your nose instead of in front of your mouth. The controller hears "pfff... dum dum dum" instead of words.

5. Talking while doing something else. Turning a knob, looking for a chart. It shows. The voice is strained or fragmented. Hand off first, then press PTT.

6. Repeating your message before the controller's readback. "HB-PMR cleared to land 19, cleared to land 19" — double readback is redundant and confusing. Once is enough.

When the signal is poor

If the controller says "You are unreadable" or "Say again", three things to do in sequence:

  1. Check the mic: positioned correctly? Headset connected?
  2. Slightly change aircraft position: terrain (mountains) blocks VHF. Sometimes 200 ft higher makes the difference.
  3. Speak more slowly, not louder. Reduced speed compensates for noise.

If the problem persists and you suspect the radio, there's the blind transmission procedure — see Radio Communication Failure.

The role of preparation

Pilots who speak well on the radio weren't born that way. They did two things:

  • Wrote out their calls before transmitting them, while learning. The mental "script" comes from there. After 50 written flights, it starts coming out automatically.
  • Listened a lot before speaking. LiveATC, local frequencies on the ground, recordings. The ear learns to recognize the "right" rhythm.
Practical exercise

Record yourself with your phone simulating a radio call (e.g. VFR clearance request from Lugano to Locarno). Listen back. Count fillers. Count swallowed endings. It's brutal, but two weeks of daily practice changes everything.

Summary — to remember

  1. Cadence ~100 words/minute, with micro-pauses between logical blocks.
  2. Normal volume, not shouted. Mic 2-3 cm from your mouth.
  3. Pronounce endings, especially final "r" and "t" in English.
  4. PTT before and after: 0.3-second buffer at both ends.
  5. Zero fillers. If you need to think, release PTT.
  6. Listen a lot before speaking. The ear trains the voice.

Sources

  • ICAO Doc 9432 — Manual of Radiotelephony, Chapter 2 (Speech Technique)
  • Aero Locarno · Subject 090 — VFR Communications, "Speech technique" chapter
  • EASA Acceptable Means of Compliance — Part-FCL — Communication standards
Want to go beyond theory?

The wiki gives you the parts. The course teaches you to assemble them.

VFR Essentials is the video phraseology course for people who really fly — with real Swiss airfield scenarios, real ATC audio, and the perspective of someone on the other side of the microphone.

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