This table is used only when you use the Segment window to interact with your contacts.
When you select an interaction template in the Segment window, all the interaction template languages are copied to this table. This allows you to modify attachments without modifying the templates in the Interaction Template Languages table.
You can create new segment interaction languages that you want to use in the Segment window, or you can delete any segment interaction language that you do not want to use.
If the contacts on the segment lines have a preferred language specified for them, the preferred language will automatically be assigned to them. If, for example, you select DEU as the segment interaction language, then this language will be assigned to the contacts in the segment with the language code DEU (see also Language Code and Language Code (Default).