How to limit number of chars featured text

In the front page I need to limit the chars of the featured text from a featured page. If not, in the featured text is shown all the text in that page.

I leave the field blank because I need a multilanguage site, so if the excerpt is from the page, it is in the language selected (I use qtranslate). If I write only the chars that I’d like to see in the field, the text will be only in one language..