5. The computing system of claim 1 , wherein the lexicon generator further comprises a confidence assignor, for each word sequence identified in the messages of a selected context, a confidence score based upon the count of occurrences of the word sequence among the messages of the context; and wherein the lexicon generator further generates the lexicon based upon the confidence scores assigned by the confidence assignor component to respective word sequences of the context.
5. The computing system of claim 1 , wherein the lexicon generator further comprises a confidence assignor, for each word sequence identified in the messages of a selected context, a confidence score based upon the count of occurrences of the word sequence among the messages of the context; and wherein the lexicon generator further generates the lexicon based upon the confidence scores assigned by the confidence assignor component to respective word sequences of the context. 6. The computer system of claim 5 , wherein the confidence assignor assigns the confidence scores for the respective messages by: for respective word sequences, identifying the count of the occurrences of the word sequence among the messages of the respective contexts over time; and assigning the confidence scores to the respective word sequences according to the count over time of the occurrences of the respective word sequences among the messages of the respective contexts.