OK, sorry to hijack, but following this thread with great interest (and have read other thread linked to).
DS2 is 19.5 months, with a big brother who talks non-stop & followed the usual 'milestones' for speech/languages. DS2 does not have any words at all. He babbles - dada, dayday, deardear, yehyeh, a a a. He also makes surprised/interested noises (two-tone kind of 'ooh/oh')
The thing that really concerns me is that he doesn't point at things that interest him in the distance (well, has done so twice). He points at things in books (although not eg where's the cow?), and at facial features, but he does not point at eg the tractor in the field. HV came round when he was almost 18m, as I was panicking, & she said it was fine as he waves (on demand mostly) & claps (on demand & after others do). She also said it was to be expected as I was 23m when I first talked.
He communicates in other ways - looks at me when he finds a toy funny, has started bringing change mat when done a poo, brings me toys (also holds phone up for me to speak on). He also laughs at/with his brother, as well as at pictures/tv/sounds. He shakes his head/pushes hand away if he doesn't want any more food/drink.
He follows simple commands - no, sit down, come here, get in your highchair (sometimes), give it to Mummy, put it in the box. He mostly responds to his name, unless he is otherwise engaged.
He is a very affectionate child & often climbs on people's laps for cuddles (mostly me, but also, randomly, another mum at toddler group!). He also loves to climb!
He is very laid back & has been quite slow to do everything so far - crawled at 12m, walked at 17m, clapping at 17m, waving at 18m, self-feeding in last couple of months. DH thinks he is just lazy & I compare him too much to DS1 who was the opposite of this, but I do worry!