I've just had my first properly interactive telephone conversation with my grand-daughter, who is full of cold and will be 18 months old on Tuesday next week.
It involved me singing Head, Shoulders, Knees & Toes with her in which, I'm reliably informed, she carried out the actions at the appropriate moments, and, when I asked her if she'd like another song, she said "Yes." I then asked if we should sing "Twinkle twinkle" and she said, being bunged up, "Twickle". I heard her mum, misunderstanding, saying "Do want a tickle?", and we then sang "Twinkle twinkle little star." At the end, I said, "May I speak to mummy again?" and she called "Bubby!" and that was that.
Very gratifying!