Intelligibility of Long-Distance Emergency Calling

Area of Science:

• Human-computer interaction
• Acoustic communication
• Emergency response

Background:

• Effective long-distance communication is crucial during emergencies, particularly when electronic systems fail.
• Assessing non-electronic methods for emergency calling is vital for survival scenarios.

Purpose of the Study:

• To evaluate the identification of emergency calls made without electronic assistance over varying distances.
• To determine the impact of vocal training, word structure, and call type on long-distance call intelligibility.

Main Methods:

• Participants (15 callers, 41 recorders) engaged in a closed-set word identification task.
• Callers received training in loud phonation and yodeling techniques.
• Calls (yodeled/non-yodeled, single/multisyllable words) were recorded at distances up to 170m.

Main Results:

• Call identification significantly decreased beyond 100m.
• Multisyllable words were better identified than single-syllable words beyond 25m.
• Nonyodeled calls were identified more accurately than yodeled calls beyond 50m, though yodeled calls had higher sound levels.

Conclusions:

• Even brief vocal training enhances long-distance call identification.
• Multisyllable words and non-yodeled calls improve intelligibility at greater distances.
• Further research on training duration and environmental factors is recommended.