SystemLanguage.Unknown

Указывает, что язык операционной системы неизвестен.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Start()
    {
        //This checks if your computer's operating system is in an unknown language
        if (Application.systemLanguage == SystemLanguage.Unknown)
        {
            //Outputs into console that the system language is unknown
            Debug.Log("This system is in an unknown language. ");
        }
    }
}