In 1995, Betty Hart and Todd Risley published a study that found that working class families and those being served by welfare experience what we now refer to as the "30 million word gap."
En 1995 Betty Hart y Todd Risley publicaron un estudio que mostraba  que las familias trabajadoras y aquellos dependientes del  estado de bienestar social experimentan lo conocido como la "brecha de 30 millones de palabras".