Out-Law / Your Daily Need-To-Know
Google has been granted a patent for a system that provides search results from a voice query, five years after its application was filed with the US Patent and Trademarks Office. Co-founder Sergey Brin is listed among the inventors.
Also featuring in the list of inventors are Alex Franz and Brian Milch who co-authored a paper in 2002, Searching the Web by Voice, which considered a speech interface for Google for settings where typing on a keyboard is impractical.
The patent application reflects the paper. The difficulty of applying speech recognition to web searches is explained: most queries are short, just five or six words; and a large vocabulary is needed – yet even a vocabulary of 100,000 words only covers about 80% of the query traffic. The paper addresses the problems and solutions such as a likelihood ratio, applying this to collocations (e.g. a search on "New York flowers" should combine New York + flowers, not New + York Flowers), constructing language models, analysing perplexity results, etc.
The paper suggested that a commercial speech recognition engine could return the correct transcription of a spoken search query among its top 10 hypotheses about 60% of the time.
According to the abstract of the patent, entitled Voice interface for a search engine:
"A system provides search results from a voice search query. The system receives a voice search query from a user, derives one or more recognition hypotheses, each being associated with a weight, from the voice search query, and constructs a weighted boolean query using the recognition hypotheses. The system then provides the weighted boolean query to a search system and provides the results of the search system to a user."
