For a lot of lines, it is essential that the emphasis fall on the correct word. Kids don’t always understand this. Often it indicates that the actor doesn’t understand the meaning of the line. Below is an exercise that demonstrates the importance of phrasing. Take the sample sentence: I can't tell you how to do it.
I can’t tell you how to do it.
Emphasizing the word “I” indicates that though I can’t tell you how to do it, there may be someone who could.
I can’t tell you how to do it.
This indicates that I’m not able or willing to give out the information on how to do it.
I can’t tell you how to do it.
This phrasing indicates that I might be able to show you how to do it, I just can’t explain it.
I can’t tell you how to do it.
This indicates that I could tell someone else how to do it, but I can’t tell YOU how.
I can’t tell you how to do it.
This indicates that though I know what to do, I am unable to explain how it’s done.
I can’t tell you how to do it.
This indicates that though I may know what needs to be done, I don’t know how it is done.
I can’t tell you how to do it.
This indicates that I could explain how to do something like it, but I can’t explain how to do this particular thing.