People with limited verbal abilities or who are unable to speak will need adapted communication. Some people sign, some people use a device, others learn to spell/write. There are a wide varieties of ways to communicate. Here are some links to some information about these different types of communication for people with alternative needs.
Project Core : Website that demonstrates the “core” vocabulary that researchers indicate that children are most likely to use and should be exposed to on a general basis.
Here are a handful of products that some people use for AAC and that may be useful.
Proloquo2go: One of the most commonly used AAC programs. This is an iOS program that can be downloaded to any Apple product (though is most commonly used on an iPad). It is a bit pricey at $250-$300, but many individuals swear by it.
TouchChat: Another iOS program, coming in around $299. However, this one can also be put onto designated devices, meaning insurance is more likely to cover it.