layout.css

a:after {
  ...

  content: attr(title); /* Default to title */

  ...
};
 
html.js a:after {
  ...

  content: attr(data-title); /* Shift to data-title */

  ...
};

layout.js

jQuery(function ($) {

  $('html').addClass('js'); // add .js to the html element

  // Take existing titles and move them to data-title instead
  $('a').each(function (i,el) {
     $(this).attr('data-title', this.title)
            .attr('title', ''); // empty out title
  });
  
  
});