using System;

using System.Text.RegularExpressions;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var stringJson = "{\"PT\":\"adssadsadsd \"asdada\"\",\"ES\":\"\",\"FR\":\"\",\"EN\":\"\"}";

        var lista = RetirarAspas(stringJson);

        var testeJson = "{";

        foreach (var linha in lista)

        {

            Console.WriteLine(linha);

            testeJson += linha + ", ";

        }

        testeJson += "}";

        var jsonDesserializado = JsonConvert.DeserializeObject<dynamic>(testeJson);

        Console.Write(jsonDesserializado);

    }

    public static IEnumerable<String> RetirarAspas(string jsonString) 

    {

        var regex = new Regex("(\")([\\w]+)(\")(:)(\")([\\w\\s\"]*)(\"),?");

        var teste = regex.Matches(jsonString);

​

        foreach (Match match in teste) 

        {

            String linha = "";

            for (int i = 1; i < match.Groups.Count; i++) 

            {

                if (match.Groups[i].ToString() == "\"") 

                    linha += "'";

                else

                    linha += match.Groups[i].ToString();

            }

            yield return linha;

        }

    }

}

​