Abstract: In this paper, we put forward a new viewpoint of two kinds of human language(internal and external), which iffers from that of one kind of language with twofashions(sound and soundless) in most books of linguistics and sychology (1～14)We establish a model of internal language, in which perception presentations consistingof ensation presentetions and concepts by multiple recursion are important basic elem-ents, and image and logic are nified. Then we describe external language systematically.Relations between internal & external languages and hinking, inspiration phenomenon, andrelation between knowledge & language understanding and internal & external anguagesare discussed. Finally, we bring up some important questions for intelligence computerresearch.