5. The device according to claim 1 , further comprising a converter to convert a lattice structure obtained by the voice recognition result into a trie structure.
5. The device according to claim 1 , further comprising a converter to convert a lattice structure obtained by the voice recognition result into a trie structure. 6. The device according to claim 5 , wherein the converter includes a generator to generate, from the voice data, a word lattice having a voice recognition score; an extractor to, from each arc of the word lattice, extract M number of best arcs in descending order of the voice recognition scores, M being an integer; and a storage to store therein identification information, which is used in identifying the M number of best arcs that are extracted, in a trie tree.