Results when focusing search field
Browser Screen reader OS Result
Chrome 51 VoiceOver Mac OS 10.11 Reads ”ellipse, insert at start of text, Search label, text”
Firefox 47 VoiceOver Mac OS 10.11 Reads ”Search label, text”
Safari 9 VoiceOver Mac OS 10.11 Reads ”ellipse, Search label, search text field”
IE10 NVDA 2015.3 Windows 8 Reads ”Search label, edit, blank”
Chrome 46 NVDA 2015.3 Windows 8 Reads ”Search label, edit, blank”
Firefox 41 NVDA 2015.3 Windows 8 Reads ”Search label, editable, autocomplete, blank”
IE10 JAWS 13 Windows 8 Reads ”Search label, edit, type in text”
Opera 36 JAWS 13 Windows 8 Reads ”Search label, edit, ellipsis, ellipsis”
IE9 JAWS 15 Windows 7 Reads ”Search label, edit, type in text”
IE9 Window-Eyes 9.4 Windows 7 Reads ”Search label, edit”

Comment: Chrome and Safari (Mac) seem to be the only browsers that read placeholder text, so far. Safari seems to still read the placeholder text even when there is another value inside the text field.