DD is 18 months and doesn't say any words, even Mama or Dada. She went through a phase when she was about a year of saying 'a' for 'cat' but that stopped after a few weeks. She went through a phase a few months later of 'nana' for 'banana' but that also fizzled, though she does still sometimes make a nanana type sound when she's asking for fruit after dinner. She has occasionally said 'mama' or 'dada' with a lot of prompting and modelling but has never really said it spontaneously. She babbles all the time but not in a particularly 'conversational' way, just talking to herself really. She shows no interest in copying words or sounds. If I ask her to say a word she just points to the object / person or makes a 'nah' sound.
Apart from this she seems to be a very effective communicator. My sister (who has had 3 kids herself) doesn't see her often but looked after her for the day a few weeks ago and remarked how well she communicates even without words. She loves books and listens happily to quite long stories like Mog the Forgetful Cat. Obviously I don't know how much she takes in but she seems engaged with it and can point to pretty much anything you ask in the pictures. She can follow some simple instructions like 'shut the cupboard door' or 'give me the ball' and can point to lots of body parts.
I haven't been worried about it up to now as her understanding has always seemed so good. I've just figured she doesn't see the point of talking as she makes herself so well understood. However, DH has just read an article about how young children with speech delay can 'fool' you into thinking they understand more than they do and now I'm questioning myself. Maybe when I think she's following an instruction it's something she would do anyway, or she's going off other cues like gesture? DH tried giving her some instructions which were more out of context like putting a random toy on the table and she didn't do it. But maybe that kind of thing is just too abstract for her at this stage?
Should I be worried? Maybe the fact that she doesn't seem to retain any words should be setting off more alarm bells?