1DS has discovered the letter S and how to use it at the end of a word to make it plural. When counting he used to say - one cup, two cup, three cup, etc. Now he is saying - one cup, two cups, three cups, etc. We've been practicing sssssssss, making the sound a lot. It's so much fun to watch him learn and discover. I enjoy the smallest things that most parents probably take completely for granted.