12. A morpheme analyzer, comprising: an information acquirement unit configured to acquire a morpheme analysis target and additional information associated with the morpheme analysis target, from search index data; a key creator configured to create a key based on the additional information in response to the information acquirement unit acquiring the additional information; and a morpheme analyzing unit configured to analyze a morpheme of the morpheme analysis target by using the key, wherein the key creator comprises: a plural key creator configured to create a plurality of keys by performing a morpheme analysis for each information included in the additional information; and a combined key creator configured to create a combined key by combining the plurality of keys, and wherein the morpheme analyzing unit comprises: a determination unit configured to determine whether the morpheme analysis target includes a partial character string corresponding to the key; and a partial character string adder configured to temporarily add the partial character string in a morpheme dictionary in response to determining that the morpheme analysis target includes the partial character string corresponding to the key.
12. A morpheme analyzer, comprising: an information acquirement unit configured to acquire a morpheme analysis target and additional information associated with the morpheme analysis target, from search index data; a key creator configured to create a key based on the additional information in response to the information acquirement unit acquiring the additional information; and a morpheme analyzing unit configured to analyze a morpheme of the morpheme analysis target by using the key, wherein the key creator comprises: a plural key creator configured to create a plurality of keys by performing a morpheme analysis for each information included in the additional information; and a combined key creator configured to create a combined key by combining the plurality of keys, and wherein the morpheme analyzing unit comprises: a determination unit configured to determine whether the morpheme analysis target includes a partial character string corresponding to the key; and a partial character string adder configured to temporarily add the partial character string in a morpheme dictionary in response to determining that the morpheme analysis target includes the partial character string corresponding to the key. 20. The morpheme analyzer of claim 12 , wherein the key is not separated into a plurality of portions in analyzing the morpheme.