Question

How can I split a string of around 300 (n) words into an array of n/30 strings of 30 words?

Answer 1

You can use Regex.Matches:

string[] bits = Regex.Matches(input, @"\w+(?:\W+\w+){0,29}")
                     .Cast<Match>()
                     .Select(match => match.Value)
                     .ToArray();

See it working online: ideone