Alternative language
Navigate to module Products and click the button corresponding to the desired element.

Add
Click +Add button.

Provide the requested information.
1. Name: Type the name of the product in the alternative language.
MandatoryDatatype→alphanumericMax length→40 characters
2. Description: Type a short description for your product in the alternative language.
OptionalDatatype→alphanumericMax length→80 characters
3. Language: Select from the list the alternative language.
MandatoryDatatype→list

4. Save: Click in the save button to save the changes.
You can apply the same procedure to add more translations to the available languages.
Edit
From the translations list, click in the button corresponding to the language you want to edit.

Provide the requested information the same way that you did to add.
Remove
From the translations list, click in the button corresponding to the language you want to remove.

This action doesn't has warning message due to is easy to add again the translation in case of an error.