DD4 (so I think has to learn to talk fast and talk loud) is 19 months and has between 50 and 60 words. A month ago she probably had 40.
She can say animal names and noises, Mummy, Daddy, Granny, all her sisters names, car, bus, baby, more, drink, book, 'read it' tea, peepo, bear, gone, body parts, door, up, down, carry, pushchair, no, yes, bubble, bath, turtle. Those are just the ones off the top of my head!
She is putting 2 words together now which she wasn't a month ago.
BUT she is the 2nd fastest speech wise of my children and having been around lots of the little darlings I'd say is ahead for her age at the moment. I know your experience with DC1 was different to normal but try not to worry, IME they all end up at the same place in the end!