1. First download Google Voice Search.
2.Open Google Voice Search and close it.Make sure data connection is off.
3. Download the file from attachments.
4.Extract the files.
5.Install Root Browser.
6.Open Root Browser and go to /data/data/com.google.android.googlequicksearchbox then open app_g3models.In the Folder If a folder en-us exsists, then delete it.And, create a new folder en-US and paste the files which you obtained from the attached files.After pasting close the root browser.
7. Open Google Settings , then go to search , then voice ,then change the language to English(US).After that , reboot the phone and its all done.