21. The method of claim 19, wherein the predetermined condition requires the score of the text segment against the language model for the topic of interest to be the lowest score among the scores of the text segment against the plurality of language models, and that the next lowest score among the scores of the text segment against the plurality of language models be greater than the score of the text segment against the language model for the topic of interest by more than a predetermined amount.
21. The method of claim 19, wherein the predetermined condition requires the score of the text segment against the language model for the topic of interest to be the lowest score among the scores of the text segment against the plurality of language models, and that the next lowest score among the scores of the text segment against the plurality of language models be greater than the score of the text segment against the language model for the topic of interest by more than a predetermined amount. 22. The method of claim 21, wherein the predetermined amount is zero.