Obviousness

As a technical patent analyst, I must adhere strictly to the provided information. The "Prior art keywords" section for US7398209 B2 lists "user," "information," "queries," "utterance," and "context," and the "Prior art date" is 2002-06-03. However, the provided patent text for US7398209, specifically the sections related to prior art, does not enumerate specific prior art references (e.g., other patent numbers, publications, or products) that would be typically used in an obviousness analysis under 35 U.S.C. § 103.

Without specific prior art references to combine, it is impossible to:

1. Identify combinations of prior art references that would render the claims obvious.
2. Explain why a person having ordinary skill in the art would have been motivated to combine them.

Therefore, I cannot complete the requested obviousness analysis in the manner specified.

However, I can describe the general state of the art and the problems the invention aimed to solve, as described in the patent itself, which implicitly defines what was known at the time. The patent identifies the following issues with prior systems:

• A machine's ability to communicate with humans in a natural manner remained a difficult problem.
• Human interaction heavily relies on context and domain knowledge, which machine-based queries (often highly structured) fundamentally lacked, making human questions and machine processing "incompatible".
• Existing natural language processing and speech recognition systems were generally "unable to provide a complete environment for users to make natural language speech queries and receive natural sounding responses".
• Significant barriers remained to creating a complete natural language speech-based query and response environment.
• Most natural language queries were incomplete, ambiguous, or subjective, making it difficult to transform them into machine-processable form and return natural language responses.
• Managing and evaluating complex and uncertain queries while maintaining real-time performance was a significant challenge.

The invention of US7398209 B2 sought to overcome these deficiencies by providing a "complete speech-based information query, retrieval, presentation and command environment" that makes "maximum use of context, prior information, domain knowledge, and user specific profile data to achieve a natural environment". It also emphasizes "probabilistic and fuzzy reasoning at several stages of the process" to handle partial failures and promote natural responses.

To perform a proper obviousness analysis, specific prior art documents would need to be identified and evaluated against the claims of US7398209 B2, followed by an articulation of how a person of ordinary skill in the art would have been motivated to combine elements from those specific references to arrive at the claimed invention, with a reasonable expectation of success. This step is currently not possible with the information provided regarding prior art references.