1. A voice query extension method, comprising: detecting voice activity of a user from an input signal and extracting a feature vector from the voice activity using a computer; converting the feature vector into at least one phoneme sequence and generating the at least one phoneme sequence; matching the at least one phoneme sequence with words registered in a language dictionary, extracting a string of the matched words with a linguistic meaning, and selecting the string of the matched words as a query; determining whether the query is in a predetermined first language, and when the query is not in the first language as a result of the determining, converting the query using a phoneme to grapheme rule, and generating a query in the first language; and searching using the query in the first language.