General, linguistics

Phonaesthesia and synesthesia in sign language

The term "phonaesthesia" or "sound symbolism" doesn't only refer to speech (aural-vocal modality) but also includes the visual-spatial modality of language. Examples of English symbols and ASL symbols will be described below.

What is Phonoaesthesia?

The term "phonaesthesia" or also known as "sound symbolism" is defined as the phenomenon of particular sound clusters or sequences which become associated with a particular meaning.

Unlike onomatopoeia in which a word resembles something, a word doesn't resemble something what sounds like (in spoken language) or what looks like (in signed language). Rather, it seems that language evolves in some way out of synesthesia, connecting human senses of language with language symbols.


A group of English words like snort, sneeze, sneer, snarl, sniff, and snob is associated with nose. The "gl" in words such as glass, glare, glow, glisten, glitter, glimmer, and glaze suggests shininess. The words starting with "f" such as fly, flee, flow, fluid, and flicker suggest lightness and quickness. (Crabtree and Powers). There are more but a few of these give you the idea.

In signed language, specifically American Sign Language (ASL), has a version of phonaesthesia. The handshape "8" (either thumb-open or closed) is found in a group of the ASL signs: HATE, SICK-OF, AWFUL. These signs suggest negative feelings. With the same handshape, another group of the signed words TOUCH, TASTE, CONTACT, SENSITIVE and FEEL, suggests a "feeling-ness" sense. SICK, MEDICINE -> a sense of health.

The handshape "8" has other symbolism that is suggestive of emptiness such as EMPTY, NAKED, NUDE, SPACE-EMPTY, AVAILABLE, NOT+AVAILABLE, BALD, HAND-OFF.

Note that clusters of phonoaesthesia-oriented words don't mean all other words with the similar sounds or visues are in those clusters. Often other words have nothing to do with phonoaesthesia.

Examples of location-based senses

In addition, a location-based phonaesthesia of the signed words such as GOOD-RIDDANCE-OF, NOSEY, PURPOSEFULLY-REVENGE, LEARN-LESSON-BIG-TIME (or LEARN-NOT-DO-AGAIN) suggests "curse-ness" or along the line.

Examples of size-based senses

Another thing, vowels (vowel height) along with consonants in English words reflect perception of size. The vowels in these words "teeny", "small", and "tiny" feel small. And, the words "large", "big", "huge", and "enormous" feel big.

In parallel, the ASL signs SMALL, SHORT-HEIGHT, and LESS are signed either smaller or convergent. Many of these signs come with the mouth morpheme "oo".

The location-based phonoaethesia of the signs is horizontal in DEAD while the signs LIFE/LIVE and INSPIRE are upward or vertical.


Synesethesia is defined as: "a condition in which normally separate senses are not separate. Sight may mingle with sound, taste with touch, etc. The senses are cross-wired." (

Or, in other words, it is described by msn encarta as:

1. physiology sensation felt elsewhere in body: the feeling of sensation in one part of the body when another part is stimulated

2. psychology stimulation of one sense alongside another: the evocation of one kind of sense impression when another sense is stimulated, e.g. the sensation of color when a sound is heard

3. literature rhetorical device: in literature, the description of one kind of sense perception using words that describe another kind of sense perception, as in the phrase "shining metallic words" ( literary )

I find synesthesia interesting when it comes to language. Let's explore a few research studies that might be applied to language-related synesthesia.

The Bouba and Kiki Experiment

According to Wolfgang Köhler's "booba/kiki effect" study, 95% to 98% of people choose "kiki" for the sharp, angular shape and "booba" (or "bouba") for the soft, rounded shape. The subjects in this experiment most likely were hearing.

booba and kiki

As a visual-manual speaker without hearing, I still can clearly identify the booba and kiki. To verify my hypothesis in circa 2008, I have informally tested on some deaf subjects including my Deaf parents and relatives, and they appeared to be the same result despite their deafness.

Interestingly furthermore, as I fingerspelled these visual-phonetic words, I discovered that in manual alphabet, the handshapes K and I are also angular and sharp, whereas the handshapes B and O are round and gentle.

booba and kiki
Illustration by Jolanta Lapiak, 2008 or earlier.

As research shows that sense is synesthetic, this kiki-booba in fingerspelling suggests that perception is synesthetic and language is intermodal.


It's no surprise that Deaf people, especially Deaf artists, explore and experience music in a different way from hearing people. Through some Deaf artists' works on the concepts of music and sound, music is no longer associated with sound, just like language is no longer possessed by speech nor sound. Rather, it's synesthetic from a new perspective, such as vibrational and visual.

Brain and Language

The vocal-auditory and visual-manual modalities are quite opposite. Yet, the activities in brain of these languages, English and Ameslan (ASL) for example, in different communication modes, are similar.

Research studies showed that, when processing ASL language, the prelingually (native) signers (deaf or hearing), who learned ASL from birth, use the same linguistic-specific activity in the brain as hearing people when processing English language.

This shows that the regions of the left brain, which is responsible for language, is not based on sound-speech, as it has been previously believed to be. Regardless of the modalities (vocally speaking, manually speaking, or writing), language appears to be also synesthetic as well as intermodal.


M. Crabtree and J. Powers. "Arbitrariness in Language." Linguistics of American Sign Language, ed. by C. Valli and C. Lucas. Gallaudet Univ. Press, 2000.

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