We have had the benefit of having my in-laws staying with us for several months again. Alas, all good things come to an end and they returned to China. My son is especially sad because that means he had to go back to day care. And he reacted the same way as before. With marathon crying sessions (he has the endurance that befits the son of two marathon runners.) But by the end of the first week, he was at the point where he was not crying all the time. And we suspect he even played enough to learn a song or two. He has never been good about playing with other kids, so that would be the next milestone to hope for.
This month also saw being more engaged with the world. Doors are meant to be opened and passed through. Button's are to be pushed.
He has turned into a little recorder, with a surprising ability to repeat words. Fortunately, these have been pleasant surprises, like 'Fiddlesticks', not embarrassing ones :-) There are a number of books in the bedtime rotation that he know can say most of the stories. I joke that when it is bedtime his job is to read to daddy, not the other way around. Current favorites are "Someone is coming to this house (a story of the nativity from the point of view of barn animals anticipating a visit) and A Book of Sleep (a story of an owl observing everyone else going to sleep at night). Before he started day care we went to a performance night at the daycare and taught him some of the songs and dances that they learned there. That was very easy to pick up and we can set songs on repeat for him to dance away on his own.
Next goals: playing well with others. Hopefully daycare will help here.