Words frequency with LINQ

frequency.cs

var str = "The quick brown fox jumped over the lazy dog. Hello-world! wOrLd WorLd. The new order!";

var words = 
	new Regex(@"\b([A-Z-]+)\b", RegexOptions.IgnoreCase)
	.Matches(str)
	.Select(m => m.Groups[0].Value.ToLower())
	.GroupBy(g => g)
	.Select(g => KeyValuePair.Create(g.Key, g.Count()))
	.OrderByDescending(kv => kv.Value)
	.ToDictionary(kv => kv.Key, kv => kv.Value);

words.cs

private static readonly Regex word = new Regex(@"\b([a-z]+)\b", RegexOptions.IgnoreCase | RegexOptions.Compiled);

static void Main(string[] args)
{
    File.ReadAllLines("WordFile.txt")
        .SelectMany(s => word.Matches(s).Select(m => m.Groups[0].Value))
        .GroupBy(w => w.ToLowerInvariant())
        .Select(g => Tuple.Create(g.Key, g.Count()))
        .OrderByDescending(t => t.Item2)
        .Take(20)
        .Select(t => t.Item1)
        .ToList()
        .ForEach(Console.WriteLine);
}