Sensory-Motor Period (birth to 2 years)

Language skills are “physical”: children are learning to imitate adults’ movement. Language is used for communication of wants and needs. Language is not essential to thinking or problem-solving.

For example, infants might point to the high chair and utter a word r sound to communicate that they want to eat.

Pre-Operational Period (2 years to 7)

Language is considered egocentric because children see things purely from their own perspective. Another part of the reason for the egocentricity of the child is that a significant part of their language involves gesture, movements and sounds. Egocentric speech is divided into 3 categories:

Repetition (echolalia): repetition of words and syllabus for the pleasure of talking, with no thought of talking to anyone; it is devoid of any social character.

Monologue: the child is talking to him/herself as though thinking aloud.

Dual or collective monologue: the conversation is related to the action at the moment, but children do not expect others to attend or understand what they are saying; the others’ point of view is not taken into account. The others in the situation serve as stimulus.

The child's mind is largely syncretic—the child’s thoughts are directly connected with immediate observation, whether these are accompanied by language or not.

Concrete operational (7 to 12)

Children's language becomes "symbolic" allowing them to talk beyond the "here and now" and to talk about things such as the past, future and feelings.

Between ages 7 and 8 children’s language shows signs of verbal syncretism. Because children think in terms of 'schemas', they focus on the whole of a message without having to make sense of every detail. When they hear something they do not understand, children do not try to analyze the sentence structure or words but try to grasp or create an overall meaning.

Language also becomes socialized with the advent of concrete operations. Socialized speech is divided into 5 categories:

Adapted information: the child exchanges ideas with others and may pursue a common goal in collaboration with others. A child adopts the point of view of the others who are not chosen at random but rather have some common interests.

Criticism: the child makes remarks about the work or behaviors of others which may give rise to arguments, quarrels and emulation.

Commands, requests and threats: the categorization of these depends on the conventions adopted in the context and are separated into categories for convenience.

Questions: these call for answers by the children in the context.

Answers: these are meant to respond to real questions and to commands. They are therefore different from remarks.

Between ages 7-8 the child knows what it means to give a correct rendering of the truth – that is, the difference between invention and reality.

Operational (12 years to adulthood)

The teenager's ability to reason, think abstractly, make judgments and consider future possibilities made them essentially the same as an adult. They can “de-centre” or view things from other people’s perspectives. From this point on development is a matter of increases in ability rather qualitative changes.

Language at this stage reveals the movement of their thinking from immature to mature and from illogical to logical.

Child’s age

Infancy and Toddlerhood: 0-2

Language communicates needs and wants to others. Speech is preintellectual; thought is preverbal. (Vygotsky 1987)

Preschool age: 2-3

Thinking and speech merge: speech is used for thinking. Thinking and speaking occur simultaneously. The child speaks about what they are doing. The speech and action become one and the same complex psychological function that is directed towards to problem-solving. (Vygotsky and Luria 1994) In complex situations (a multistep task), the child uses speech to help form ideas related to the problem at hand. Without speech, these ideas may be too vague to act on. This speech is called private speech—speech directed to self that has self-regulatory role. It is often abbreviated and sometimes not completely explicit because it is not directed to others but to the child him/herself.

Private speech does not disappear completely even in adulthood but become less audible with time. In adults, it becomes inner speech or verbal thinking; sometimes adults use private speech when trying to trace their steps back in looking for something that seems to be misplaced or learning a new complex task.

Late preschool and school age: (4-10.

Speech separates into private and communicative/public. Private speech becomes inner speech and then verbal thinking. Inner speech in completely nonaudible and may retain some of the characteristics of the external/public/communicative speech in that sometimes even adults hear the words in their heads but do not say them aloud (as in preparing ahead for an important conversation). In this case, inner speech become verbal thinking which Vygotsky described as “folded” so that people can think of several things at the same time. (Vygotsky 1987)

At the beginning, unfolding the verbal thinking takes a mental effort to draw ideas back to the consciousness.

Adolescent to adulthood

Verbal thinking becomes automated—solving a mathematical problem that involves addition no longer requires “unfolding” the mental steps required in the operation of addition. However, even after some operations are atomised, both children and adults can return to previous levels of the development of thinking and need to use speech to clarify concepts or understand complex concepts. Talking about them with someone else helps understanding.

Written speech/writing is not just oral speech on paper but a cultural tool that helps the development of higher-level thinking. Written speech forces inner thoughts into visible sequence that can be revisited and improved over time.

It serves the following functions:

• Makes thinking more explicit and reveals any gaps and flaws in it.
• Makes thinking and the use of symbols more deliberate, both language and image to communicate meaning to an audience that is not immediately present.
• Makes the child aware of the elements of language and how the organization of thoughts according to rules (i.e., paragraphs, applying the laws of syntax) helps communicate meaning.