This is working on one of my sites, a demonstration site, but not the other, the live site. On the demo site inspecting the tooltip element give
<span class="cbTooltip" data-cbtooltip-tooltip="Check the box if you do not want to receive news from IFA via mass email. You will still receive email regarding your account." data-cbtooltip-title="Opt Out of IFA Emails" data-hasqtip="35">
on the live site the element is
<span class="cbTooltip" data-cbtooltip-tooltip="" data-cbtooltip-title="Opt Out of IFA Emails" data-hasqtip="10">
On both sites if the field icon display is set to show info text the text is displayed, so the language override text substitution is loaded for the text display on both and on the tooltip display on the demo site, but not the tooltip display on the live site.
Richard Brundage