See [this](https://wordpress.org/support/topic/can-subtitle-be-outputted-through-jetpack-testimonial-shortcode?replies=2). It should be fairly easy to do this, since we've already done it with Jetpack the portfolio module.
See this. It should be fairly easy to do this, since we've already done it with Jetpack the portfolio module.