I hate to hear your having problems with Siri. Let's get this addressed quickly. Did this start after you downloaded an application? How is your signal strength in this area?
Please disable and re-enable the Siri function. To do this go to: Menu> Settings> Siri.
The reset the device and retest. Here's a link to the reset: http://support.verizonwireless.com/clc/devices/knowledge_base.html?id=47670
Please let me know if you still run into any problems with Siri.
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