List<string[]> threeGrams = new List<string[]>();
                int wordCount = nonEmptyWords.Count;
                for (int i = 0; i < wordCount - 2; i++)
                {
                    string[] threeGram = new string[3];
                    for (int j = 0; j < 3; j++)
                    {
                        threeGram[j] = nonEmptyWords[i + j];
                    }

                    threeGrams.Add(threeGram);
                }

                threeGrams.Add(new[] { nonEmptyWords[wordCount - 2], nonEmptyWords[wordCount - 1]});
                threeGrams.Add(new[] { nonEmptyWords[wordCount - 1] });

                foreach (string[] threeGram in threeGrams)
                {
                    output.Set("MeetingId", meetingId);

                    output.Set("SubjectThreeGramWord1", threeGram[0]);

                    if (threeGram.Length >= 2)
                    {
                        output.Set("SubjectThreeGramWord2", threeGram[1]);
                    }
                    else
                    {
                        output.Set<string>("SubjectThreeGramWord2", null);
                    }

                    if (threeGram.Length >= 3)
                    {
                        output.Set<string>("SubjectThreeGramWord3", threeGram[2]);
                    }
                    else
                    {
                        output.Set<string>("SubjectThreeGramWord3", null);
                    }

                    yield return output.AsReadOnly();
                }