I have the following string in a variable.
Stack Overflow is as frictionless and painless to use as we could make it.
I want to fetch first 28 characte
I would use a string tokenizer to split the string into words much like this:
$string = "Stack Overflow is as frictionless and painless to use as we could make it.";
$tokenized_string = strtok($string, " ");
Then you can pull out the individual words any way you want.
Edit: Greg has a much better and more elegant way of doing what you want. I would go with his wordwrap() solution.