SystemLanguage.English

Description

Indicates that the operating system's language is English.

using UnityEngine;

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