specially和specifically意思还有用法有区别么?

specially和specifically意思还有用法有区别么?老师讲义里给出的句子：Since many teenagers are in the formative years,smoking is highly injurious to their physical health,specially,due to the fact that tobacco contains too much chemical substances,smoking will be pernicious to teenagers’ physical progress.这句中间的specially,他明明讲课时说的是“确切的说specifically,”但写在讲义上的却是specially,并且他自己还在那说了一遍拼写,说的字母是s-p-e-c-i-a-l-l-y,可是给完拼写字母说单词却说的specifically的读音!说的跟写的完全不是一个词,而且他重复说了几遍,我听都是specifically.查字典看意思又好像差不多,究竟这两个词有什么不同,是不是这里用哪一个都可以?还是只能用某一个,另一个不对?