From 12 to 18 months, many children have 2-3 words or more that they can reliably say, some do not. More important than verbal expressive language is your child's ability to understand you, called receptive language, and ability to nonverbally communicate what he wants. As you give him food and objects, name them, and use books as a way to ask him to point at objects after you name them.
Nothing is more fun at this age than reading! While some kids can sit still at this age, others can't, so don't give up hope if your toddler is too wiggly to settle in for a reading session. Make it interactive and fun. Most importantly....be persistent!