you need to speak english here.为是么要用to

need to do sth这里的need是实意动词,如果不用to的话就成了need作为情态动词的用法,need do sth.这句话意思是“在这里你得说英语”（说别的语言就怕别人都不懂）.need do sth什么意思 need to do sth什么意思表示should do something or has to do something应该做或不得不做某事need do sth什么意思 need to do sth什么意思need to do sth 表示should do something or has to do something应该做或不得不做某事用作情态动词时一般不单独说need do something。但可以在疑问句或表示疑问的从句中用，如I asked him whether he need go.也有少数情况下可以在肯定句中用I‘ll help you any time,you only need ask.(和only连用时）。更多情况下need当作情态动词时是用在否定句和疑问句中，如Need I tell Tom?Nobody need be afraid of catching the disease.