From Nerve Signal to Hearing: How We Perceive Sound
Nerve impulses travel from the hair cells to the brain via the auditory nerve, undergoing processing at several stations including the brainstem and the thalamus. These signals reach the auditory cortex in the temporal lobe, where they are interpreted as tones, sounds, or voices. Understanding this process is crucial for diagnosing and treating hearing loss and related conditions.
A significant amount of this processing occurs before we consciously register a sound. The brain filters and evaluates signals, determining which noises deserve our attention. It emphasizes specific acoustic features like frequency and volume even as suppressing others, allowing us to focus on a single voice and tune out distracting background noise. This filtering can also lead to the perception of sounds even without an external source, as experienced in tinnitus or auditory hallucinations.
The Mechanics of Speech
But how do we produce speech? “A tone is exhaled, vibrating air brought to life – the result of a complex process,” explains psychologist and phoniatrics expert Christiane Kiese-Himmel. It all begins with exhalation: air from the lungs passes through the larynx, where the vocal cords are located. These two elastic bands of tissue vibrate as air flows past them, creating initial tones.
The vibrations created are then modified and amplified as they pass through the vocal tract – encompassing the pharynx, oral cavity, and nasal passages. Movements of the tongue, lips, and facial muscles alter the sound, enabling the articulation of different vowels and consonants.
Temperature’s Influence on Sound
Environmental factors can also influence the sounds produced during speech – an aspect that has historically been underestimated in research. “For a long time, research assumed that linguistic structures were self-contained and not influenced in any way by the social or natural environment,” explains Søren Wichmann of the University of Kiel.
Recent studies, however, demonstrate a correlation between the average ambient temperature of a region and the volume of certain speech sounds. Analysis of thousands of languages and dialects revealed that languages in warmer regions tend to be more resonant or “louder” than those in colder regions, a phenomenon known as increased “sonority.”
The reason? Cold, dry air makes it difficult to produce loud vowels through strong vocal cord vibration. Warm air, conversely, carries voiced sounds well but dampens high-frequency voiceless consonants. These differences may have led to the development of linguistic structures with higher sonority in warmer climates over many generations.
February 20, 2026 – Carolin Malmendier
