He's had proper nouns for some time: Mum, Dad, and other extended family members (including Nana's dogs - very important).
Other nouns he generally signs. Except barber - Grandma taught him to say that one and it comes out a lot, especially as he's desperately in need of a hair cut.
Verbs he also signs, or imitates. It surprises me how accurately he can reproduce an action that he's only seen a small number of times.
SP's favourite part of speech at the moment: prepositions! Up, in, out & on mostly. Useful for almost any situation. I never realised how many different phrases and contexts include 'up' until it became SP's favourite word to imitate. Apart from the obvious directional meaning, there's clean up, pack up, fix up, tie up, makeup, and many more that I can't think of right now.
Here's SP yesterday, reading up on local news and events...