When I was in first grade, I broke my arm at a school skating party. Just call me 'Grace'! (I had a knack for hurting myself.) I didn't go to the hospital right away, though, because we couldn't tell by looking at it that it was broken. It was an injury on the inside that needed 'special eyes', an x-ray, to see what the naked eye could not.
And, so it is with a broken heart. It's a hurt on the inside that no one else can see. Especially if a person has well-developed coping mechanisms, a broken heart can be even harder to detect. They smile their way through their day. They run to the bathroom to cry and wait to 'melt' when they are by themselves. Even to their closest friends and family, it is hard for them to show on the outside the trauma that has taken place on the inside.
But, "Special Eyes" see it all. Though man only looks at the outward appearance, God looks straight into the depths of us. Nothing is hidden from His Sight. And funny enough, He knows us more than we even know ourselves. So, when it's all just too deep for words and we don't even know how to pray, we can be speechless with Him and He still completely gets it. No explanation needed.