"Actually" as a sentence-starter of speech filler When casually speaking English I use the word "actually" a lot at the beginning of a sentance, or as part of the flow of my speech. e.g.


  Actually, next semester doesn't start for a month.
  
  Actually, I don't have any siblings.


I would like to be able to continue this speech habit in Mandarin Chinese, I have been using 事实上 (shìshíshàng), but from my listeners' reactions I am not sure if this is really the same.

What is the closest equivalent expression?
"其实" or "其实呢" is more similar to what you wanted, casually. E.g.


  其实我没有兄弟姐妹.


"事实上" is not wrong, but it is literally "in fact" or "as a matter of fact".