code: function trainTuples(words) {
    var probs = {};
    var count = 0;
  
    words.forEach(function(w) {
      w = clean(w);
  
      for (var i = 0; i < w.length - 1; i++) {
        if (!probs[w[i]]) probs[w[i]] = {};
        if (!probs[w[i]][w[i + 1]]) probs[w[i]][w[i + 1]] = 1;
        else probs[w[i]][w[i + 1]]++;
        count++;
      }
    });
  
    Object.keys(probs).forEach(function(first) {
      Object.keys(probs[first]).forEach(function(second) {
        probs[first][second] = percent(probs[first][second], count);
      });
    });
  
    return probs;
  }
docs: Extract probabilities of word t 	uple.