Black and White text effect?

Hi there

I have some english text and an arabic text character together on a page, they are both black with white background as you can see here: https://postimg.org/image/5gh92r2hv/

I would like to know how when the black english text runs into the black arabic character how can i get it to turn white and then back to black as it leaves again? The colour of the english text being effected by the curved line of the arabic character.

As you can see i have just the stroke to make it noticeable.

Thank you!