12. A computer-implemented method of selecting boundaries for application of a paraphrase alternation pattern to an input string, the method comprising: utilizing a computer processor that is a functional component of the computer to apply the paraphrase alternation pattern multiple times to the input string with multiple boundaries so as to create a plurality of alternation alternatives, wherein each alternation alternative is a different sequence of words included in the input string; generating a language model based on a set of test data and then applying the language model to the plurality of alternation alternatives to determine which, based on frequency within the set of test data, is a relatively commonly used sequence of words; and wherein applying so as to create a plurality of alternation alternatives comprise applying so as to switch different combinations of words around a word in the input string identified as being a pivot word.
13. The method of claim 12 , further comprising determining whether the paraphrase alternation pattern can be applied to the input string so as to preserve meaning.