Lingua.iso_code_639_1_for_language

You're seeing just the function iso_code_639_1_for_language, go back to Lingua module for more information.
Link to this function

iso_code_639_1_for_language(language)

Get the ISO 639-1 language code for the given language.

Example

iex> Lingua.iso_code_639_1_for_language(:english)
{:ok, :en}
iex> Lingua.iso_code_639_1_for_language(:nope)
{:error, :unrecognized_language}