Methods and apparatus to classify text communications are disclosed. An example method includes determining a first conditional probability of a first feature occurring in a text given that the text belongs to a classification mode, wherein the first feature is included in the text, determining a second conditional probability of a second feature occurring in a text given that the text belongs to the classification mode, wherein the second feature is included in the text, determining a probability of the classification mode occurring, multiplying the first conditional probability, the second conditional probability and the probability of the classification mode to determine a product, and storing the product in a tangible memory as a score that the message belongs to the first classification mode.