/indra/newview/skins/default/xui/en/widgets/talk_button.xml

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<!-- Derives from LLUICtrl -->
<talk_button>
  <!-- To make speak button look green when selected set:
    image_selected="SegmentedBtn_Left_Selected"
    image_unselected="SegmentedBtn_Left_Off"
  -->
  <speak_button
    follows="left|right" 
                 image_selected="SegmentedBtn_Left_Selected_Press"
                 image_unselected="SegmentedBtn_Left_Off"
		 image_pressed="SegmentedBtn_Left_Selected_Press"
		 image_pressed_selected="SegmentedBtn_Left_Selected_Press"
    tab_stop="false"
    />
  <show_button
    follows="right" 
    name="speak_flyout_btn"
    label=""
    left="0"
    top="0"
    right="20"
    bottom="0"
    tab_stop="false"
    is_toggle="true"
    image_disabled="ComboButton_UpOff"
    image_unselected="ComboButton_UpOff"
    image_selected="ComboButton_On"
    image_pressed="ComboButton_UpSelected"
    image_pressed_selected="ComboButton_Selected"
    />
  <monitor
    follows="right" 
    name="monitor"
    left="0"
    top="18"
    right="18"
    bottom="0"
    />
</talk_button>