That makes sense…
Use the export tool in the first site and then the import tool in the second site to bring in everything. That will get you started but you’ll have both sites in English until you translate.
Take a look at the Syndicate Out plugin to deal with new posts and I’m going to figure you plan to use some plugin to deal with the translation?
I don’t know much about using other languages but Syndicate Out will trigger on new posts on the first site. That trigger will send the new post to the second site via XML as a new post once you’ve set up the plugin.
So then you’ll have the version in the first language on the second as a new post. Hopefully, a new posting on the second site will trigger whatever translation system you’ll want to use and that new post will get translated properly.
It shouldn’t be too hard to get Syndicate Out to push the new posts over as drafts or Pending posts either if that is necessary to ensure the translation process is done well.