Speech and language disorders in children can be conceptualized as falling into two categories: developmental and acquired. Within the category of developmental, we can also distinguish between developmental delay and developmental disorder. Developmental language delay refers to delay in the acquisition and development domains. This can be due to medical or psychosocial factors. A developmental language disorder is characterized by atypical development of langage skiils in one or more domains, often with aberrant or interrupted development. There are specific milestones associated with each age as a child acquires speech and language skills. It is important to minitor development and watch for any signs that might indicate delay or disorder. The following is a list of danger signals of communication problems by age:
儿童言语语言障碍可以分为发育性及获得性两大类。发育性又可以划分为发育延迟和发育障碍。发育延迟是指在由于医疗或者社会心理学的原因导致语言获得、语言发育等领域方面的延迟。语言发育障碍则以一个或多个领域的语言技能异常或者发育中断为特征。孩子在各个年龄阶段的语言言语技能都有特定的标志，重要的是去监测孩子的发育情况，细心观察任何可能提示发育延迟或障碍的信号。

By 6 months 6个月___  
# Does not respond to the sound of others talking  不能对其他人的谈话声音有反应
# Does not turn toward speaker out of view  不能将头转向视线外的说话者
# Makes only crying sounds  仅能发出哭的声音
# Does not maintain eye contact with caregiver  不能与照顾他的人有较长时间的视线接触

By 12 months 12个月___
# Does not babble  没有咿呀发音
# Does not discontinue activity when told "no"  当被告知“不要”时不能停止当前活动
# Does not follow gestural commands, such as "want up"  不能跟从手势指令，比如“起来”

By 24 months 2岁 ___
# Does not say a meaningful word  尚不能说出一个有意义的词
# Does not refer to self by name  不能提及自己的名字
# Does not follow simple directions  不能理解简单的方位词
# Does not talk at all 2 years  完全不能交谈
# Vocabulary does not seem to increase  词汇量似乎没有增加
# Does not have any consonant sounds  不能说任何的辅音
# Does not answer simple yes/no questions  不能回答简单的是/不是这一类问题

By 36 months 3岁___
# Does not say whole name  不能说出完整的姓名
# Does not seem to understand "what" and "where" questions  似乎不能理解诸如“什么”、“哪里”这一类的问题
# Uses jagon a great deal  仍使用过多的儿语
# Answers your question by repeating the question  重复别人的提问（而不是回答问题）
# Continues to echo statements made by others  机械性地重复别人的话
# Does not use two-to three-word utterances   不能说2-3字句
# Points to desires objects rather than naming them  用手指向想要的东西而不是说出来
# Does not name any objects in pictures  不能说出图画中任何物品的名称
# Leaves off the beginning consnants of words  省略声母（说话不清楚）
# Cannot be understood even by parents  说的话即使是父母也听不懂
# Does not respond when you call name  呼叫其名字时无反应