21. A device comprising: a processor; and a computer-readable memory coupled to the processor and containing instructions that when executed by the processor cause the processor to: determine a plurality of sections of training text in which each section of training text is associated with a geographical region; accumulate occurrences of a string in the plurality of sections of training text when terms to a left or right of the string are different from previous instances of the terms to the left or right of the string; and generate a histogram that defines the geographical relevance of the string with respect to geographical regions based on the accumulated occurrences of the string.
24. The device of claim 21 , where the string comprises a bi-gram.