Compare the accessibility choice as well as the title
Two downloads of a film need not occupy the same space if they were prepared with different accessibility preferences. Before concluding that storage reporting is faulty, note whether sign language was enabled when the download was made. Also check that the compared items are the same film or episode, rather than different editions or several episodes grouped under one series tile.
Read Apple’s explanation of the additional file
Apple’s iPhone and iPad TV-app settings guide says that enabling Sign Language uses interpretation when available. It explains that downloads are approximately twice the original file size because an additional ASL or BSL version is downloaded alongside it. This describes a supported accessibility preparation choice, not an unexplained duplicate created by the viewer or a general promise that every programme includes signing.
Plan the local library around the intended viewer
Suppose one tablet is being prepared for a viewer who needs the signed version. Preserve that required edition when reviewing space; deleting it simply to match the size of another tablet would defeat the preparation. Instead, choose the programmes needed for the trip and inspect available storage before building the whole library. A programme saved for another family member may have different accessibility requirements.
Verify availability before disconnected use
Confirm the intended version can be selected while a suitable connection remains available. The existence of the setting alone does not establish that a particular title has sign-language interpretation. If storage is tight, make a deliberate choice about which items to retain rather than disabling an accessibility preference without the viewer’s agreement. Keep this download-size explanation separate from the language of ordinary dubbed audio.
Questions, answered
Does enabling the preference guarantee signing for every title?
Apple scopes sign language to programmes for which an interpreted version is available.