using System;

        using Newtonsoft.Json.Linq;         

public class Program

{

    public static void Main()

    {

        var json=JObject.Parse("{\"results\": [ {\"alternatives\": [ {\"transcript\": \"how old are you\", \"confidence\": 0.66882694 } ] }  ]}");

        var result = json["results"][0]["alternatives"][0]["transcript"];

        Console.WriteLine(result.ToString());

    }

}