This study investigates the similarities and differences between adult and children naturally occurring conversation in the uses of the Mandarin particle LE. Previous studies have identified the use of LE in Mandarin as a marker of perfect (S-le), perfective (V-le), and comment-LE (C-le). C-le has recently been proposed in Chang's study (2003). This work is primarily devoted to the functions of S-le and C-le in child speech and further comparing their similarities and differences with adult discourse as in Chang's study. The use of Chinese LE expression in child conversational discourse is relevant to ongoing activities. Actions have decisive consequences in shaping the trajectory of talk's development in real time. Also, the use of LE utterance in child conversational discourse is highly correlated with speakers' social action and signals a projected completion point (e.g., turn projection and turn extension). One distinctive similarity between the use of LE utterance in adult and child conversation is that S-le utterance appears a lot more frequently than C-le utterance. However, there is a striking difference of C-le occurrence in child and adult conversation; children barely use C-le utterance in their speech. C-le is a new usage of LE utterances and seldom appears in adult speech and it may be expected to be less frequent or not to be nearly seen in child speech. Besides, younger children's talks are more likely to be factually related to the prior turn rather than to respond to the feelings or attributes expressed by the prior turn like adults do. Accordingly, it is plausible to expect to have less C-le than S-le occurrences in child conversation.
