1. A dictionary registration apparatus comprising: a first storing unit that stores therein dictionary information in which a first text in a first language is associated with a second text that is a translation of the first text into a second language; a first input unit that receives a first input text in the first language; an extracting unit that extracts, when the first input text includes an unregistered text that is not registered as the first text in the dictionary information, the unregistered text from the first input text; a determining unit that determines a part of speech of the unregistered text and that, in accordance with the part of speech, determines whether to convert a pronunciation of the unregistered text into an expression in the second language; a converting unit that converts the pronunciation of the unregistered text into the expression in the second language when the determining unit determines to convert the pronunciation; a second input unit that receives a second input text in the first language, the second input text expressing the unregistered text with a text being different from the unregistered text when the determining unit determines not to convert the pronunciation; a translating unit that translates the second input text into the second language; and a registering unit that registers the unregistered text in association with the second input text translated into the second language on the dictionary information or that registers the unregistered text in association with text which is the expression in the second language converted from the pronunciation of the unregistered text, on the dictionary information.