The apparent size and position of the letters at a certain point size (or pixel size), is determined by the size of the letters – for Latin fonts, the lowercase letters in particular – in relation to the units per em (UPM) and the vertical metrics in the font. The apparent size of Latin fonts also vary quite a bit though. Something that looks as big as Georgia, will look to big next to Garamond.

tl;dr: it depends on how big the letters are relative to the size of the «em».

Hello
You have to redesign the Latins, but it is not too difficult. In Fontlab open a full-height Latin glyph like H, go to Tools/Action/Contour/Scale tool to make a Latin outline smaller until it matches the required height and width you like to match the non-Latin. OK. Command Z to redo and try another number. Experiment with various vertical and horizontal percentages until you find a suitable scale. You can apply the same scaling to all selected Latin glyphs.

If the resulting Latin outline is too thin, try the Tools/Action/Effects/Bold (and check the "keep glyph dimensions" box) and again experiment with how many points you want the stroke width and height to be increased by, to approximate the non-Latin. (Use negative numbers to make a font outline thinner).
Good luck. It will not be a perfect Latin, but at least it will not look too strange next to the non-Latin. Can you post an example of the two scripts together?

http://caniuse.com/#feat=font-size-adjust

Thank you all,,

Actually designing Latin letters and numerals are hard and long time solution

I just checked some non-Latin fonts like Google Droid Arabic, it doesn't has Latin letters but the font fallback is very scaled to arabic!
http://www.google.com/fonts/earlyaccess

This is why I am looking for solution instead of designing Latin letters!