Check the stored language choices
In the device Settings app, open Apps and TV, then inspect the download options and Languages. Identify which audio languages are intentionally selected. A household may have added several for a previous trip or viewer and no longer need the same combination.
For example, retaining two languages for a bilingual session can be a deliberate choice, while carrying several unused tracks into every future download may not be. Do not assume a particular number of megabytes per language: the guide states that size increases, not a universal amount for every film.
Keep audio description and quality separate
Apple also says audio descriptions are downloaded when enabled in Accessibility settings. Preserve that choice if it is needed. Removing a useful accessibility track merely to minimise a file can undermine the purpose of the offline viewing plan.
The guide separately offers High Quality and Fast Downloads. Compare these controls as distinct contributors to the planned transfer rather than treating any one switch as an exact file-size calculator. The options shown can depend on the device, and the actual title still determines which tracks exist.
Verify the next download instead of assuming old files changed
Choose the language combination you want for future preparation, then inspect a newly completed authorised download and its available tracks. Do not assume that editing a preference retroactively rewrites every file already stored unless the app explicitly confirms that result.
For an offline session, confirm the needed audio and text before removing existing copies. Keep the film, device and selected language list with any support question. A smaller successful download is useful only if it still provides the presentation you intended, so assess storage, completion and accessibility together.
Questions about this guide
Can extra audio languages increase the file size?
Apple explicitly says each added audio language increases download size.
Are audio descriptions another relevant setting?
Apple says they are also downloaded when Audio Descriptions is enabled in Accessibility settings.