The Google Mobile App now includes voice search capability for BlackBerry devices. Google Search by voice lets you quickly search the web for whatever you need by speaking your search terms. To use Google Search by voice, follow these steps:
1. Launch the Google Mobile App.
2. Hold down the call button
3. Speak your search terms when you see the 'Speak Now' alert.
4. Release the call button.
After speaking your query, your search results will appear immediately. You can perform a new search by holding down the call button again, or entering a new query with the keyboard.
Google Search by voice is currently only available on newer BlackBerry phones with software versions 4.2 and higher. If it's supported on your device, you'll see the option to enable Voice Search within Options.
Google Search by voice is tuned for American English, British English and Canadian English by default. It is not currently available in other languages. You can switch between American English and British English through the 'Options' menu. If you are using Google Mobile App outside of the US, and want to enable Search by voice in English, select Yes under 'Enable voice search' within the 'Options' menu.
Source: Google