curl --request POST \
  --url https://api.x.com/2/media/subtitles \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": "1146654567674912769",
  "media_category": "TweetVideo",
  "subtitles": {
    "display_name": "English",
    "id": "1146654567674912769",
    "language_code": "EN"
  }
}
'

{
  "data": {
    "associated_subtitles": [
      {
        "display_name": "English",
        "id": "1146654567674912769",
        "language_code": "EN"
      }
    ],
    "id": "1146654567674912769",
    "media_category": "TweetVideo"
  },
  "errors": [
    {
      "title": "<string>",
      "type": "<string>",
      "detail": "<string>",
      "status": 123
    }
  ]
}