How do I make changes only to a certain text font inside a documen

[Mekalor]

I have a large document that has Japanese characters and normal English and I
want to make changes only to the Japanese text, modify size colour etc

I'm using Word 2007.

 

[grammatim]

In the Find/Replace dialog (Ctrl-H), put the cursor in the Find What?
box and go to More > Format > Font, and in the drop-down box for
"Asian fonts," choose the font you use for Japanese.

Then put the cursor in the Replace With box, go to Format > Font, and
choose the color, size, etc. that you want.

(You can now click Less if you want.)

Click Find Next and Replace, and if it does exactly what you want, go
ahead and click Replace All.

(If you have footnotes, you'll probably need to do it a second time
with the cursor somewhere in a footnote.)