How to change the description language in the openweathermap API in Android

In my application, I want to use openweathermap API to display the weather information of the city. Therefore, I want to change the description language to Persian. I got this through openweathermap help. I write the following URL:

http://api.openweathermap.org/data/2.5/forecast/daily?q=tehran,ir&cnt=16&units=metric&lang=Farsi-fa&appid=1487dd8a93bfd85d278d9ayty875ghyy

But tell me this message:

{
    "city": {
        "id": 112931,
        "name": "Tehran",
        "coord": {
            "lon": 51.4014,
            "lat": 35.7006
        },
        "country": "IR",
        "population": 7153309
    },
    "cod": "200",
    "message": 1.31599,
    "cnt": 16,
    "list": [
        {
            "dt": 1522310400,
            "temp": {
                "day": 29.68,
                "min": 9.13,
                "max": 29.68,
                "night": 9.13,
                "eve": 19.21,
                "morn": 29.68
            },
            "pressure": 749.02,
            "humidity": 67,
            "weather": [
                {
                    "id": 801,
                    "main": "Clouds",
                    "description": "few clouds",
                    "icon": "02d"
                }
            ],
            "speed": 1.42,
            "deg": 211,
            "clouds": 20
        }
}

In the openweathermap help, say that if you add this code to the URL lang = Farsi FA, change this line "description": "Shaoyun" language

I add language code but don't change the description language!

How can I do this? Please help me

resolvent:

It should be just language code:

lang=fa

http://api.openweathermap.org/data/2.5/forecast/daily?q=tehran,ir&cnt=16&units=metric〈=fa&appid=1487dd8a93bfd85d278d9ayty875ghyy

"description":"بارش خفیف باران"