Publishing multi-language Sitecore items leads to a large amount of items being processed

When you publish a Sitecore item that has multiple language versions, you see that the item is processed multiple times. For example, if you have an item in Danish, English, and German versions, the publishing process will look like this:

This is a known behavior of the AddLanguagesToQueue Sitecore processor.

For more details on the behavior of the AddLanguagesToQueue processor and a solution to minimize its overhead, see Publishing in Multilingual Sitecore Sites - Reducing the Overhead.