To call buttons for another language, you’ll need to do a couple of things.
First, I recommend you just duplicate the template you have in skin/frontend/default/. For example, if you have skin/frontend/default/hellococo folder, then make a skin/frontend/default/hellococo-language folder, and copy the contents of the skin/frontend/default/hellococo into skin/frontend/default/hellococo-language.
So now that you’ve just duplicated your template in another folder, you have the freedom to change EVERYTHING about the new language, including images, css, and locale translations. But you also need to go to System–>Design and change the “Skin (Images / CSS)” of that store to “hellococo-language”. Remember to select the proper store for this change in “Current Configuration Scope” in the top left dropdown, because if you select “Default config” then you’ve basically only switch where Magento reads your template from.
Now you can go into the skin/frontend/default/hellococo-language/images folder and replace all your English images with new translated ones. Yes, this is a pain, but once it’s done it looks so professional! Also you can rename the template folder “hellococo-language” to whatever you want. This will appear in image links and may be crawled by search engines, so make it clear.