Tuning Sounds into Words
Dolphins, whales and humans are among the animals that use sounds to
communicate more complicated meanings, using strings of sounds of some duration.
The idea of a “word” is based on the recognition of a short burst of sound waves
and the association of this sound with a built-in dictionary of standard
meanings. The brain lexicon or “dictionary” associates words with memories of
experiences. Words gain deeper meaning by repeated association with experiences.
Words that derive meaning by association with other words are less meaningful.
Dictionaries that relate words to other words reveal little about the
experiential meaning of words.
Words often act as signals that activate specific responses. Some words are
powerful and elicit strong responses automatically and other words are natural
and indifferent.” God” and “Fuck” are strong words. “The, and, is “are neutral
words. Rude or obscene words tend to be instant triggers of emotional responses
if they are unuttered in the wrong context. The strong emotional response to
some words and not others is evidence that some sounds act at receptors for
immediate emotional responses. Direct-acting sounds cause responses before they
become conscious. These direct-acting sounds have a different brain presentation
than words of a more neutral and abstract nature that require more elaborate
decoding and do not trigger emotional responses.
Speech has evolved from ancient animal sound communications. Humans speak
naturally and spontaneously. Children learn the language spoken around them.
Speech is mimetic and is connected to body language and non-speech
vocalizations. Arm and hand motions are closely linked to words and can take
over communications if you cannot speak. Speech functions are concentrated in
the temporal and frontal lobes of the brain with different right and left
allocation of function. Speech required at least two brain innovations that
increase sound processing ability:
1. A fast and reliable “working memory” that hold word sounds briefly so that
the meaning of sentences can be assembled.
2. A larger, long-term storage of word sounds a brain dictionary of sounds
that is well integrated with other domains in the brain. A small number of
sounds are combined to form a much larger number of words.
The production of words involves specific adaptations of the human vocal
tract that compromise other functions such as breathing and swallowing. The
trachea is longer and the vocal cords in the larynx obstruct airflow to produce
word sounds. The nose and throat act as sound resonating chambers that help to
shape word sounds. The tongue and lips form consonants. The brain is adapted to
coordinate airflow with all the sound-shaping movements that articulate sounds.
Sound shaping movements are coordinated with all other communicative movements
of the eyes, face, head, arms and trunk. Speaking is a whole-body, kinetic
activity. Concepts flow from whole body kinetic activity in the form of
metaphors based on movement in spacetime.
Human auditory perception is adapted to the specific demands of decoding
speech sounds into linguistic segments. The temporal lobe receives sounds and
tunes into sound features that form phonemes by separating waveforms that carry
meaning from a stream of other sounds. In most languages, pitch and volume
variations form part of the semantic meaning.
In all languages, pitch and volume variations carry emotional meaning, linked
to the semantic content. Binder et al used functional magnetic resonance imaging
to show that sound identification occurs just in front of the primary auditory
cortex and activation of the inferior frontal region was associated with the
response to a sound.
A small collection of standard sounds (phonemes) is required to make a
language. The sounds are stored in the temporal lobe of the left hemisphere in
most right-handed people. You learn words by hearing phoneme combinations as
morphemes, and you imitate making the sounds. Words obtain meanings by
association with a rich array of different kinds of memories that are linked to
sound experiences. Humans acquire the sounds that form the local language
as children and then shut down the phoneme library at about age ten. The younger
you are, the easier it is to learn one or more languages.
