You have to $compile
your inner html like
.directive('autotranslate', function($interpolate, $compile) {
return function(scope, element, attr) {
var html = element.html();
debugger;
html = html.replace(/\[\[(\w+)\]\]/g, function(_, text) {
return '<span translate="' + text + '"></span>';
});
element.html(html);
$compile(element.contents())(scope); //<---- recompilation
}
})