I have, for quite some time now, been playing "peek-a-boo" with Léa. I generally make all the sounds hoping she'll catch on.
Today, she wanted me to actively play with her so started to gently cover her head with my hand and quickly take it away. I wasn't saying anything. After maybe 4-5 times, she was the one to say "peek-a-boo" once I removed my hand. This is the first time it happened and both the Boy and I heard it loud and clear. She also said it on another occasion a few minutes later.
Guess she did finally catch on!