(1) Language: It is a special social phenomenon consisting of a certain system of pronunciation, vocabulary and grammar. Language is felt and perceived by people in the form of materialized sounds and glyphs. It is a product of social history.

(2) Speech: Speaking is the process in which people use language materials and language rules to communicate. It can be divided into oral speech, written speech and internal speech according to the form of expression.

(3) The relationship between language and speech 1. Language and speech are two different concepts. 2. Language and speech are inseparable.

(1) External speech 1. Conversational speech. 2. Monologue speech. 3. Initial written language.

(2) Excessive speech: A form of speech between external speech and internal speech, "transitional speech", that is, self-talk aloud.

(3) Inner speech: It is a special form of speech. It is directed at one's own speech and does not perform communicative functions. It highlights the conscious analysis, synthesis and self-regulation functions, which are inseparable from thinking.

(1) The process of preschool children mastering language is a process of socialization

(2) Speech and preschool children’s cognitive process

(3) The regulating effect of speech on the psychological activities and behaviors of preschool children. 1. Self-conscious analysis. 2. Comprehensive functions are closely related.

1 Acquired learning theory. 2 Innate maturity theory. 3 Theory of interaction between environment and subject.

From meaningless pronunciation to meaningful pronunciation.

From vowels to consonants.

From single to multiple syllables.

From inaccurate to progressively accurate.

Vocabulary development in infants and young children

Expansion of speech categories in infants and young children.

Infants and young children's understanding of word meaning.

(1) The development of sentence patterns. 1. Incomplete sentence stage: 1~2 years old (one-word sentence stage: 1~1.5 years old, two-word sentence stage: 1.5~2 years old). 2. Complete sentence stage, 2~2.5 years old. According to whether there are modifiers, they can be divided into two types: simple sentences without modifiers and simple sentences with modifiers. 3. Compound sentence stage 2~3 years old. A sentence that can be divided into two or more clauses that are equivalent to a single sentence.

(2) Characteristics of syntactic development.

(1) The accuracy of children's pronunciation is directly proportional to their age. 1. Physiological factors, further maturation of vocal organs, speech auditory system and With the development of brain function, pronunciation ability is rapidly enhanced. 2. Vocabulary accumulation.

(2) The leap period for speech development is between 3 and 4 years old.

(3) Children have different levels of mastery of initial consonants and finals.

(4) Phonological awareness gradually develops.

(1) The number of vocabulary gradually increases.

(2) The range of word categories continues to expand.

(3) The understanding of word meaning gradually deepens.

(1) Development of sentence structure. 1. Sentences range from simple to complex, from incomplete to complete. 2. The sentences range from without modifiers to with modifiers, and the lengths range from short to long.

(2) The development of sentence functions. From chaotic unity to gradual differentiation.

(3) Understanding of sentences. Comprehension always precedes sentence production.

(1) Development of oral expression ability.

(2) Development of verbal expression skills.