Auditory Illusions in Speech Perception: Definition and Examples

Published on February 1, 2026 | Category: Phonetics

Auditory illusions in speech perception are perceptual errors where your brain hears something different from the actual sounds produced.

If you have ever misheard the lyrics of a song ("All the lonely Starbucks lovers" - Blank Space, Taylor Swift, anyone?), struggled to understand someone on a phone call, or been certain you heard one thing when someone swears they said another, you have experienced these auditory phenomena firsthand.

In this article, I will explain what auditory illusions in speech perception are, share six interesting examples, and show how we encounter them in daily life. Scroll to the end for FAQs.

What are auditory illusions in speech perception?

Auditory illusions in speech perception happen when our brain misinterprets acoustic information, causing us to hear something different from what was actually said.

In the same way that optical illusions show how our visual system actively interprets what we see, these auditory phenomena demonstrate that speech perception is a constructive process rather than a passive recording of sound.

When we listen to speech, our brain is not just registering sound waves. It is interpreting the information quickly, using linguistic knowledge, context, expectations, and past experiences to build what we ultimately hear.

These illusions can appear in different ways. Sometimes our brain fills in missing information based on what makes sense in context. This process is called phonemic restoration. In other cases, the acoustic signal itself is ambiguous, so our brain interprets it in unexpected (and sometimes funny) ways.

This is studied in the field of auditory phonetics, which focuses on how we perceive speech sounds.

6 examples of auditory illusions in speech

These examples show how our perception of speech can differ from what the sounds actually are.

Phonemic restoration

This occurs when the brain fills in missing speech sounds based on the context around them. In a classic study, participants heard a sentence like "The state governors met with their respective legi*latures", where the asterisk represents a cough or noise replacing the "s" sound.

Listeners said they could hear the complete word "legislatures", even though part of it was actually replaced by noise. Our brain is very good at using contextual clues to figure out what word makes sense.

The Ganong effect

The Ganong effect shows that the words we know influence how we categorize vague sounds. If you hear a sound that falls somewhere between "d" and "t", you are more likely to interpret it as the sound that creates a real word.

For example, "dash" is a real word, whereas "tash" is not, so you are more likely to hear the ambiguous sound as a "d" rather than a "t".

Categorical perception

Even though sounds are part of a continuum, we tend to hear speech sounds as if they belong to distinct categories. In one experiment, people heard a synthetic speech sound recording that pronounced many sounds between "ba" and "pa".

The differences between the sounds are physically equal, but listeners reported hearing a sharp shift at a specific point, where "ba" suddenly became "pa". It was also nearly impossible for them to identify two sounds as distinct when both fell under the subjective category "ba". More on categorical perception.

The verbal transformation effect

When you listen to a word repeated continuously, you may suddenly hear it change into a different word, even though the recording has not changed.

If you experiment with the word "tress" and listen to it on repeat, you might end up hearing "dress", "stress", "rest", or even more variations. This effect shows the instability of speech perception when the conditions are unusual.

Mondegreens

The term "mondegreen" was coined by Sylvia Wright after mishearing a ballad line that said "laid him on the green", but she heard it as "Lady Mondegreen".

It generally means persistently mishearing song lyrics or speech, often in funny ways. Another common example is the lyrics "Excuse me while I kiss the sky" by Jimi Hendrix's "Purple Haze", often misheard as "Excuse me while I kiss this guy".

Unlike other auditory illusions, once a mondegreen takes hold, it often persists even after you know the correct words.

Duplex perception

Duplex perception is a phenomenon where the same acoustic component is processed in two different ways at the same time: once as part of a speech sound, and once as a non-speech sound.

For example, if the spoken syllable "da" is split into two parts, most of the syllable is played into one ear and a very short sound is played into the other ear. When heard alone, that short sound is just a "chirp".

When both parts are played together, listeners report two things at once: a clear, complete syllable "da" and a chirp sound. This shows speech is not processed like ordinary sounds, as the brain can run both interpretations in parallel.

How auditory illusions impact daily life

Auditory illusions in speech perception can affect everyday situations in a variety of ways.

Mishearing in conversation

In a noisy environment, you might miss parts of what someone said. Your brain fills in the gaps based on context and expectations. Most times it gets the gist right, but other times it adds to the confusion.

Accents and dialects

When you first hear an unfamiliar accent in a language you speak, it can feel like gibberish. Our brains expect words to be pronounced in a specific way, and when they are not, comprehension breaks until we adjust.

Phone conversations

We use visual cues (lip movements and facial expressions) to understand speech. The McGurk effect, where visual information influences what we hear, explains why phone calls can be harder to follow than face-to-face conversation.

Learning and memory

In educational settings, students might mishear instructions or technical terms and store incorrect versions in memory. This is especially common when learning a new language or specialized vocabulary, and it is harder to correct later.

Autocorrect moments

Have you ever been certain someone said one thing, only to realize they said something completely different? Phonemic restoration means our brains can literally "hear" sounds that are not there, filling in what makes sense in context.

Multilingual environments

In contexts where code-switching happens between two or more languages, the brain might accidentally apply the phonetic rules of one language to another. This creates a kind of misperception that monolinguals would not experience.

FAQs

An auditory illusion happens when you perceive speech that is different from what the speaker said, whereas not hearing something means you are aware you missed part of the message. The key difference is that with illusions, you do not realize you misheard.

Yes. Factors like your native language, hearing ability, level of attention, and familiarity with the speaker all affect how susceptible you are.

They often do. Age-related hearing loss makes the brain rely more on context and prediction, which can lead to misinterpreting speech more frequently.

Noise masks or degrades parts of the speech signal, forcing the brain to rely more heavily on context and prediction to fill in missing information.

Yes. Bilinguals may experience unique illusions when their brain applies sound categories from one language to speech in another, creating misperceptions that would not happen for monolingual speakers.

Children are generally more susceptible to certain auditory illusions because their speech perception systems are still developing and they have less linguistic knowledge to draw upon.

Song lyrics are especially susceptible because singing distorts the patterns of speech and musical elements can mask parts of the words.

Conclusion

Auditory illusions in speech perception show the complexity involved in processing speech as we hear it. Our brains are constantly interpreting, predicting what might come next, and filling in gaps based on context, expectations, and past experience.

When we understand how these illusions work, we can become more aware of misperceptions and improve how we communicate in everyday life.