code: function getNextPhonetic(phoneticSet, simpleCap, wordObj, forceSimple) {
  	var deriv = getDerivative(wordObj.numeric),
  		simple = (wordObj.numeric + deriv) % wordObj.opts.phoneticSimplicity > 0,
  		cap = simple || forceSimple ? simpleCap : phoneticSet.length,
  		phonetic = phoneticSet[wordObj.numeric % cap];
  	wordObj.numeric = getNumericHash(wordObj.numeric + wordObj.word);
  	return phonetic;
  }
docs: Gets the next pseudo-random phonetic from a given phonetic set,
  intelligently determining whether to include "complex" phonetics in that
  set based on the options.phoneticSimplicity.
  
  @param {Array} phoneticSet The array of phonetics from which to choose
  @param {number} simpleCap The number of 'simple' phonetics at the beginning
  of the phoneticSet
  @param {{word, numeric, lastSkippedPre, lastSkippedPost, opts}} wordObj The
  wordObj for which the phonetic is being chosen
  @param {boolean} [forceSimple] true to force a simple phonetic to be
  chosen; otherwise, the function will choose whether to include complex
  phonetics based on the derivative of wordObj.numeric.
  @returns {string} The chosen phonetic.