Children acquire written language on the basis of oral development (see reading psychology). Understanding speech is a process of grasping semantics through thinking on the basis of perceiving the material shell of speech (pronunciation and glyph) and relying on people's past experience.
The perception of words is mainly to grasp the sound and shape of words, and the understanding of words is to grasp the meaning of words. However, there is usually no one-to-one correspondence between word sounds or word forms and word meanings, and a word often has several meanings; The depth of understanding will also vary from person to person. Understanding a word means understanding its specific meaning. People should analyze and synthesize the position of a word in speech, its grammatical attributes, its relationship with other words and the speech environment, and then they can accurately determine its meaning. At the same time, even if the same word is in the same language environment, it is related to different meaning generalization systems for different individuals. For example, the word "hardship", although children and adults may know its meaning roughly, will have very different meanings and understanding depth for a teenager who has just learned the world and a weather-beaten old man.
Understanding sentences is more complicated than understanding words. Word order, stress and intonation are all means of grammatical or semantic expression. In Chinese, these elements all affect the understanding of sentences. The inversion of word order will cause the change of sentence meaning; The change of stress position can change the meaning of the sentence; Different intonation will make the listener have different understanding. The understanding of speech is mainly the understanding of its meaning and the understanding of its emotion. In addition, the understanding of the sentence has a great relationship with the semantic situation of the sentence. The content implied by the context of the sentence seems to limit the range of words and meanings acceptable to the listener or reader in some way, thus affecting the direction and depth of understanding to some extent.
Perception and understanding of speech are not two completely independent processes, but intertwined and coordinated with each other. Undoubtedly, the correct understanding must be based on the clear perception of pronunciation or word form, but the understanding of speech is also the other way around, which restricts the perception of speech. The reason why people can distinguish the pronunciation that deviates from the standard is the proof of participating in the understanding process. In the perception of written speech, whether it is word shape recognition or reading speed, there is no restriction without understanding factors. People can correctly find and judge single words or words that are missing or misprinted in printed matter, which shows that the thinking process compensates the perception process.