We have been saying prayers with Olivia on a regular basis for some time. She's the master of rote, able to sing back large parts of songs after hearing them once and always repeating things she hears. So, at almost two, she has memorized large portions of our meal prayers and bedtime prayers.
At meals, she's usually too hungry to comply with our request to "wait to eat until we pray". So she usually doesn't follow along before meals. But then, somewhere around the middle of her meal, she'll fold her hands and say, "Can we pray now?" So, of course, we pray AGAIN, and this time she follows along with 80% of the words.
For bedtime prayers, even though she knows most of the words, she'll usually just sit and listen. When I conclude the prayers, she'll pipe up and say, "Night-night, Jesus" or "I love You Jesus!"
At Mass, she's getting...better. But she has, on occasion, done some really cute things that tell us she's paying attention. When the priest carries the gospel book to the lectern, she'll pick up her hymnal with both hands and hold it above her head. When we kneel and pray, she'll kneel (even though she can't see over the pew) and fold her hands above her head. Not always, but when she's feeling particularly good.
It's sweet to watch.