I am looking at this movie Ip Man. When I pull through the api I get

 "spoken_languages": [
    {
      "english_name": "Mandarin",
      "iso_639_1": "zh",
      "name": "普通话"
    },
    {
      "english_name": "Japanese",
      "iso_639_1": "ja",
      "name": "日本語"
    },
    {
      "english_name": "Cantonese",
      "iso_639_1": "cn",
      "name": "广州话 / 廣州話"
    }

and

  "original_language": "cn",

This is incorrect, the ISO-639-1 standard for Cantonese is just zh since there is no differentiation in this ISO standard, 'cn' has no definition. This is not just for the specific movie I sent, its for all movies with Cantonese as one of the spoken languages.