Localization is the process of making the content local.
We learned in the Data Inheritance section that the unlocalized entries fetch data from its fallback language. You can then translate the content or make the necessary changes and localize it. To localize an entry, save the unlocalized entry. Read more on how to localize an entry.
When you localize an entry, it ceases to fetch data from the fallback language assigned to it. It breaks the inheritance from the fallback language and becomes independent. Therefore, after localizing, the changes made in the master language or fallback language will not be reflected in the localized entry.
As shown in the following diagram, localizing will cause the inheritance present between the master, fallback, and child entries to break, and an independent copy of the localized entry is created that will possess the same format of the master entry or fallback entry, but with different content.
This localized entry is now a separate entity altogether. It will have its own versioning system and publishing queue status.
Once an entry has been localized, you can unlocalize it again anytime.
Additional Resource: To unlocalize an entry, follow the steps mentioned in the Unlocalize guide.