Until 18 months my toddler showed very little interest in speaking actual words. He babbled incessantly and occasionally said real words like "mama", "dada", "all done", and "uh-oh" but had very little interest in using them on a regular basis or to regularly mean the things they actually mean. He learned how to wave and would say "Aaaaaah" while doing it, not while getting ready to go or when first arriving somewhere, but seemingly at random. He'd babble "Mamamamamama" nonstop for half an hour, but when I offered to give him a hug or ask him what he needed, he looked at me confused, like he didn't connect the sounds he was making with my arrival next to him.
I worried that my son wasn't going to get how spoken language worked. Like many parents of this generation, I was worried that my generally very social little boy was showing signs of autism, since lack of verbal communication is one of the signs, but he still communicated with me often in many other ways. He loved to goof around playing peekaboo and would yell indeterminate syllables to get my attention when he wanted me to watch him launch himself from another piece of furniture he shouldn't have been climbing (at least his need for an audience means I'm usually there to catch or pull him down from dangerous heights). He craved eye contact and attention, he just couldn't express it verbally.
And sure enough, right after Christmas spoken language started to make sense for him. He started using "all done" to more consistently mean he was done with something and "uh oh" to let us know when he'd dropped something (whether on purpose or not). When I leave the room he now runs after me screaming "Ma!" If his dad picks him up when he doesn't want to be held he screams "Nah! Nah! Nah!" (his version of "no") in addition to his usual head shaking and flailing. We play a game where he points to the different parts of his body and he's now started trying to say the parts as we do it (the "n" sound of "nose" being by far his favorite). Occasionally I even get a "thank you" out of him. And of course there are other words that are starting to come up more and more frequently, but you get the idea.
I owe a lot of my being able to find the words to write about this to a book called How Babies Talk: The Magic and Mystery of Language in the First Three Years of Life by Roberta Michnick Golinkoff and Kathy Hirsh-Pasek which is a really great overview of the research on the language abilities of babies and toddlers. Instead of selling a new fad of making your baby smarter, Golinkoff and Hirsh-Pasek simply let us know what science has been able to tell us about the language abilities of young children at various stages.
Even from within the womb, babies are learning important language skills. Does that mean you should be reading to your pregnant belly in a foreign language to give your child a leg up? Not necessarily. The authors do parents the wonderful service of explaining just how challenging understanding the concept of language and then going out and acquiring the skills to speak a language are and how the small, seemingly inconsequential milestones that our babies go through are really huge breakthroughs that our adult minds would struggle with, if they'd be able to achieve them at all.
They also show how many of the skills babies need to learn are hardwired into the parent-child relationship. It's nearly impossible to not make eye contact with a baby, and that's perfect, because babies are also hard-wired to seek out faces and making eye contact is the first way they learn to communicate.
While I picked this book up to ease my fears about my toddler's language abilities I also found it fascinating to learn the ways that the baby I'm currently pregnant with is learning to recognize my voice so that when it's born he or she will already know to find me by my voice.
Mostly I loved how this book reassured me that most of the instincts that came to me naturally, narrating my actions out loud to my child, talking more slowly and clearly to him so he could have a better chance to understand, going out of my way to make eye contact when I wanted to talk with him, are the best things I could be doing to help him develop language skills, and that while some toddlers start picking up spoken language as soon as they master walking, others take a little longer and both are perfectly normal. They also reassured me that while spoken language is the big goal for a toddler's communication skills, there are many other forms of communication that are important developmental milestones along the way (pointing being an especially big one) that are equally big achievements to first words and sentences.