I'm confused. Are you changing the page titles or the URLs?

Are you CHANGING the language from English to French? That certainly seems odd if so. That is, it was once in English, now in French, and you will no longer maintain an English version?

If that's the case (but I doubt that it is) you could do 301 redirects, which normally would preserve your standing (IF the content is not changed). But with the language being changed, I wouldn't expect it to maintain position, as it would obviously drop for English-language searches and rise for French-language searches.

If you are adding a translation along-side the original site, you're just adding new material. This shouldn't affect the standing of the original material.

Maybe you could be more precise about what you are doing and what your concern is?

Sorry it was not clear. French was just the example I used. Say for example, a completely new website was created for a translation... the original site was English, but a mirror site was created in French. So on the new site, all of this content was translated and uploaded. The only problem being that the individual HTML page names were not changed (the original pages were used as the templates for the translated site). They are still in English when they should actually be in French.

So my concern is... if I just change the page names locally (products.html to produits.html) and upload them, how will this affect my ranking in the search engines.

Having page names that match the likely French language search arguements will not hurt and may have benefits for search results. I am not sure that the work involved would be cost effective although there are goodwill considerations which may be more important.

Do make sure that page titles and descriptions are translated properly and proof read with the same care as actual page content.

So my concern is... if I just change the page names locally (products.html to produits.html) and upload them, how will this affect my ranking in the search engines.

It might lower it for some period of time, as the search engines will see these as "new" pages.

If possible, it would be best to do 301 redirects from each old English URL to the new French URL. That's what 301 is for "moved permanently".

Search engines will likely use the 301 to transfer any "history" associated with the page.

This will also help to "de-index" the old pages.

>> 301 redirects from each old English URL to the new French URL. <<

That assumes that you want the English content to be de-indexed.

Is that what you want to happen?

That assumes that you want the English content to be de-indexed.

There isn't any English content.

He created a separate French site by copying the English site and translating. But he didn't translate the URLs. Now the site is in the wild, has already been indexed by search engines, and he wants to complete the translation and translate the URLs as well.

OK. I missed that from the way I first read it.