How to convert dob to word in C#

void Main()
{
	DateTime[] dates = new DateTime[]
		{
			new DateTime(1981, 1, 28),
			new DateTime(1998, 2, 1),
			new DateTime(2000, 3, 31),
			new DateTime(2001, 4, 8),
			new DateTime(2016, 6, 5),
			new DateTime(1977, 8, 3),
			new DateTime(2012, 10, 12),
			new DateTime(1968, 12, 15)
		};

	foreach(DateTime dt in dates)
	{
		string dtw = DateToWords.Convert(dt);
		Console.WriteLine("{0} => '{1}'", dt.ToString("dd-MM-yyyy"), dtw);
	}
}

// Define other methods and classes here
public static class DateToWords
{
	private static CultureInfo ci = new CultureInfo("en-US");
	private static string[] unitsMap = new string[] { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", 
				"Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
    private static string[] tensMap = new string[] { "Zero", "Ten", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };
		
	//https://stackoverflow.com/questions/2729752/converting-numbers-in-to-words-c-sharp
	private static string NumberToWords(int number)
	{
	    if (number == 0)
	        return "zero";
	
	    string words = "";
		
	    if ((number / 1000) > 0)
	    {
	        words += NumberToWords(number / 1000) + " Thousand ";
	        number %= 1000;
	    }
	
	    if ((number / 100) > 0)
	    {
	        words += NumberToWords(number / 100) + " Hundred ";
	        number %= 100;
	    }
	
	    if (number > 0)
	    {
	        if (words != "")
	            words += " ";
		
	        if (number < 20)
	            words += unitsMap[number];
	        else
	        {
	            words += tensMap[number / 10];
	            if ((number % 10) > 0)
	                words += " " + unitsMap[number % 10];
	        }
	    }
	
	    return Regex.Replace(words, @"\ {2,}", " ");
	}
		
	public static string Convert(DateTime dt)
	{
		//convert days
		string dtw = NumberToWords(dt.Day);
		
		//convert months
		dtw += " " + dt.ToString("MMMM", ci);	
		
		//convert years
		dtw += ", " + NumberToWords(dt.Year);
		
		return dtw;
	}
}

28-01-1981 => 'Twenty Eight January, One Thousand Nine Hundred Eighty One'
01-02-1998 => 'One February, One Thousand Nine Hundred Ninety Eight'
31-03-2000 => 'Thirty One March, Two Thousand '
08-04-2001 => 'Eight April, Two Thousand One'
05-06-2016 => 'Five June, Two Thousand Sixteen'
03-08-1977 => 'Three August, One Thousand Nine Hundred Seventy Seven'
12-10-2012 => 'Twelve October, Two Thousand Twelve'
15-12-1968 => 'Fifteen December, One Thousand Nine Hundred Sixty Eight'