ActiVoice allows you to replace Siri with various functions of Google Search, it is available in Cydia

  ActiVoice is a tweak which I talked about a few days ago when I told you that through it you can replace Siri and Voice Control with the Google Search application for iOS. ActiVoice offers you the possibility to set the long press of the Home button to automatically open the Google Search application instead of Siri/Voice Control, and in the iOS Settings menu you can choose to open additional functions of the Google application: Google Googles, the text search option or Google Apps, all these functions being accessible only through the Google Search application.

  ActiVoice was until today only available in a beta repo of its developer, but starting today it is also available in Cydia's BigBoss repo from where you can install it on any iDevices.