1. A speech recognition apparatus operated by a computer for recognizing an utterance by a user, comprising: a user information processor that receives user information inputted into the computer from an external device and generates user input method information representing an utterance method of the user; a sound input device that is connected to the computer to receive a successive character string uttered by the user and converts the successive character string into sound data formed of digital signals; a recognition dictionary; a speech recognition processor that receives the utterance method of the user from the user information processor and the sound data from the sound input device to perform a speech recognition process using the recognition dictionary, wherein: the speech recognition processor requests a recognition data that is registered in the recognition dictionary and corresponds to the utterance method of the user, the recognition data including a target character to be recognized and information on the sound data in association with each other, the sound data representing a pronunciation of the successive character string including a predetermined character string and the target character subsequent to the predetermined character string, the speech recognition processor recognizes the target character from the sound data using a feature of acoustic model representing the target character, and the predetermined character string is a Japanese character string which enhances sound energy of a first phoneme of the target character when the successive character string is uttered, and pronounces as having three or more moras including “tto” as last two moras; and an output device that outputs the target character recognized by the speech recognition processor to a display device of the computer.