Please explain why?

Hello everyone,
I am reading ‘Longman Whaddaya Say-Guided Practice in Relaxed Speech’.

I don’t know why they italic the text ? What is its meaning?
Thank you very much.

In the first place it is for emphasis - I can’t sing right now this minute.

In the second place it is showing you that she is singing and the lyrics are italicised.

However, what a pity! The book didn’t give us just a bit of clue about why the text was italised.