Language development Receptive language 9mo follow one-step commands 18mo-follow two-step commands 2 ye -understand short stories 6-7ye- double denied sentences, passive sentence Expressive language 12 mo- One word 18-24 mo- two-word phrase 3 ye- completed sentence, 1000 words 4 ye- talk freely, 1600-2000 words 回复旦大学上海医学院儿科学系Language development • Receptive language 9mo — follow one-step commands 18mo — follow two-step commands 2 ye — understand short stories 6-7ye — double denied sentences, passive sentence • Expressive language 12 mo — One word 18-24 mo — two-word phrase 3 ye — completed sentence, 1000 words 4 ye — talk freely,1600-2000 words