Asian and Latin fonts

Thanks for the reply Doug but I often only want to change  a few words within the paragraph, not the whole paragraph. I often cannot select the whole paragraph because there are footnotes or endnotes within the paragraph on individual words. If I select the whole paragraph to change the font size it will change the numerical reference to the footnote and endnote also, which is not what is wanted. 

I'm not really understanding all the settings here - do you, or anyone, know of a clear explanation for setting up styles, fonts for when working with  mixed multiple script documents?  I find Microsoft help page unintelligible and they don't have pictorial examples of what I'm trying to do or an example I can relate to .
For a start, I need a clear definition of the heading used in the  Font dialog pop I showed above.