I'm wondering if it's possible to change the title and description of a single product in a feed.

You can use our app to change the titles and descriptions of specific products in the feed. This means that the product title on the shopping ad may differ from the product title on your website. This will allow you to more easily and effectively optimize your keywords.

Basically, editing translations for each specific product will be based on language on the Locale tab if you have multiple language feeds. 

It will change the title of the product from the original store's language to the feed language you specify in the rule.

As you can see in the screenshot, we included the language code, such as "fr" for French and "de" for German, “it” for Italian in the rule. This rule will apply to all French and English feeds that contain that product.

It can be explained:

If the Locale includes "fr" (French language code), the product title is changed to ....(the French title of that product you want to change)
If the Locale includes "de"(German language code), the title is changed to...(German title of that product you want to change)

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Otherwise, keep the orginal one in other feeds

Here is a video that will show you how to set that rule.: https://share.getcloudapp.com/Wnu05Oz7

If you have only 1 feed language, you simply change the title for that product at here: