1. A voice recognition dictionary generation apparatus comprising: an input unit configured to receive a text subjected to voice recognition from an external device or a medium; a storage unit configured to store therein the text with respect to each file of a predetermined item; a reading data generation unit configured to analyze the text and generate a reading data associated with a pronunciation of the text; a voice recognition dictionary configured to include content dictionaries, wherein the reading data associated with the text is stored in the content dictionaries with respect to each file of the predetermined item; and a control unit configured to store the text received via the input unit in the storage unit, wherein when a file of the predetermined item including the text stored in the storage unit is updated, the control unit detects a total number of the content dictionaries, and when the total number of the content dictionaries is smaller than a predetermined limit, the control unit generates the content dictionaries with respect to each updated predetermined item, thereby updating the voice recognition dictionary; and wherein, when the total number of the content dictionaries is equal to or larger than a predetermined limit, the control unit deletes the content dictionaries corresponding to the external device or the medium from the voice recognition dictionary, extracts all texts subjected to the voice recognition corresponding to the external device or the medium from the storage unit with respect to each content, and generates the content dictionaries, thereby updating the voice recognition dictionary.
3. A voice recognition dictionary generation apparatus according to claim 1 , wherein, when the external device or the medium is connected and the text is stored in the file of the predetermined item in the storage unit, the control unit determines that the file of the predetermined item is updated.