Functional Communication: Replacing Behavior With Words, Signs, and Pictures

When your child drops to the floor of the grocery store, or screams the moment you say “time for bath,” or grabs your face and turns it toward them, they are not giving you a hard time. They are telling you something, in the most effective language they currently have.

Functional Communication Training is built on one idea: if a behavior works as communication, teach a better way to say the same thing, and make the better way work even better.

Behavior is communication

Every behavior that keeps happening keeps happening because it works. That’s not a judgment of your child; it’s how learning operates for all of us. A four-year-old who screams during teeth brushing and gets teeth brushing paused has learned, accurately, that screaming pauses teeth brushing. A child who can’t say “play with me” but has noticed that throwing a toy brings a parent across the room instantly has found a reliable sentence.

In ABA, the “job” a behavior does is called its function: what the behavior gets or avoids. The most common functions are:

• Escape or avoidance: getting out of a demand, a place, a sensation (“get me out of this store”)
• Attention: getting a person’s eyes, voice, or presence (“look at me,” “come here”)
• Access to items or activities: getting the tablet, the snack, the swing (“I want that”)
• Automatic/sensory: the behavior itself feels a certain way, no audience required

If you want to figure out which function fits a specific behavior, our guide to the ABC model walks through how to track what happens before and after. It’s also worth ruling out that what you’re seeing is a meltdown rather than communication-driven behavior; the distinction matters, and we cover it in tantrum vs. meltdown.

What is Functional Communication Training?

Functional Communication Training (FCT) teaches your child a specific, easy communication response that does the same job as the challenging behavior, then makes that new response work faster and more reliably than the old behavior ever did.

The logic is a trade. Your child isn’t attached to screaming; they’re attached to what screaming gets. Offer a cheaper, more reliable way to get the same thing, and the screaming loses its job. FCT is a first-line strategy because it doesn’t just suppress a behavior. It replaces it with a skill your child keeps for life.

FCT has three moving parts:

1. Identify the function. What is the behavior getting or avoiding?
2. Teach a replacement that serves that exact function. A word, sign, picture, or button.
3. Honor the replacement immediately and generously, so it outcompetes the old behavior.

Why the replacement must match the function

This is the step families most often skip, and it’s the one that determines whether FCT works. The new communication has to buy the same outcome the behavior was buying. Teaching “more please” to a child whose screaming means “get me out of here” gives them a sentence they have no use for.

If the behavior’s job is…	Teach your child to ask for…	Household example
Escaping a demand	“Break, please” / break card / BREAK button	Screams during homework → hands you a break card, gets two minutes off
Getting your attention	“Mom, come here” / tapping your arm / LOOK button	Throws toys while you cook → says “watch me,” you turn and respond
Getting an item	“Tablet, please” / picture of tablet / naming the item	Grabs and shrieks at tablet handoff → asks, receives it
Ending an activity	“All done” / pushing item away gently / STOP sign	Melts down mid-haircut → signs “all done,” gets a pause

In practice this means: if your child’s behavior says “I need a break from this,” then for a while, asking for a break has to actually produce a break, even from things you’d rather they finish. That can feel like losing ground. It isn’t. A child who can ask to stop is a child you can later teach to wait, to do “one more,” to negotiate. A child who can only scream to stop cannot learn any of that.

What are the options for nonspeaking children?

FCT does not require speech. Communication is the goal; the channel is whatever your child can use right now with the least effort. Common options include:

• Speech-generating devices and AAC apps. A tablet or dedicated device where your child presses a symbol and the device speaks. Ranges from a single big button to full vocabulary systems.
• Picture exchange. Your child hands you a picture card of what they want. Concrete, portable, and requires no technology. A laminated “break” card can live on the fridge, in the car, and in your bag.
• Manual signs. Simple signs like MORE, ALL DONE, HELP, and BREAK. Fast and always available, though they only work with people who understand them.
• Gestures. Pointing, reaching toward an item, leading you by the hand, pushing an item away. Often the most natural starting point for very young children.

None of these is universally “best.” The right choice depends on your child’s motor skills, vision, what listeners in their life can understand, and what your child takes to. Giving a child AAC, pictures, or signs does not stop speech from developing; having no workable way to communicate is what truly costs a child. A speech-language pathologist (SLP) is the right professional to help you choose and customize a system.

Whatever channel you choose, the first taught message should be easier than the challenging behavior. If the behavior is a scream (instant, zero effort), the replacement can’t be a four-symbol sentence on a device buried in a backpack. One word, one sign, one card, one press.

Honor it immediately and generously

When your child uses the new communication, especially in the first weeks, respond fast and big — faster than you ever responded to the screaming. The new response is competing against a behavior with years of a proven track record; it wins by being a better deal.

• Child touches the break card → the demand pauses now, not after “just finish this one.”
• Child says “Mama” for attention → you turn, light up, engage, even if you’re mid-email.
• Child presses TABLET at handoff time → tablet arrives promptly, with warm acknowledgment.

Yes, this means honoring requests at rates that feel unsustainable: forty break requests in an afternoon, “come here” every ninety seconds. This phase is temporary and it is the treatment working. Your child is testing whether the new tool is real. Requests naturally settle as trust builds, and later, with a clinician’s guidance, you can gradually teach waiting, “first this, then that,” and tolerating “not right now.” Trying to ration the new communication too early is the fastest way to send your child back to the behavior that never got rationed.

Pair all of this with rich positive reinforcement for using the new skill. Enthusiasm, delivery of the thing, and your genuine delight all count.

Common pitfalls

Prompting too much

It’s easy to slide into doing the communication for your child: grabbing their hand to touch the card, saying “say break… say break… SAY BREAK” until they echo you. Heavy prompting can leave your child waiting for your prompt instead of initiating. Prompt as lightly as you can, fade your help quickly, and celebrate independent attempts even when they’re imperfect. An approximation your child produced alone beats a perfect response you produced through them.

The replacement is harder than the behavior

If asking requires finding an adult, getting the device, navigating two menus, and building a sentence, while screaming works from anywhere in one second, screaming wins. Audit the effort honestly. Shorten the response, keep materials within arm’s reach in every room where the behavior happens, and put a copy in the car.

Honoring the old behavior while teaching the new one

If screaming still produces escape half the time, your child has no reason to switch. The plan works when the new response pays reliably and the old behavior stops paying, which is genuinely hard in real life and is covered in depth in our guide to extinction bursts.

Only practicing during calm times, or only during crises

New skills should be taught and practiced when your child is calm and the stakes are low, then honored everywhere. Teaching only in the middle of an escalation rarely sticks; teaching only at the kitchen table and never honoring it at the store doesn’t transfer.

When should you involve an SLP or BCBA?

You can start simple versions of this at home: notice the function, model an easy word or gesture, honor it fast. But bring in professionals when:

• The behavior involves aggression, self-injury, or anything unsafe. A BCBA should assess the function formally and design the plan before you change how you respond.
• Your child is nonspeaking or minimally speaking and needs a communication system selected and customized. That’s SLP territory, ideally in collaboration with a BCBA.
• You’ve tried for a few weeks and the behavior isn’t budging, which usually means the function was misread or the replacement isn’t competitive.
• You’re heading into an evaluation process and want communication support built into the plan from the start.

Every child’s plan should be individualized by someone who has actually observed your child; what’s written here is the map, not the route. But the destination is the same for every family: a child who doesn’t have to fight to be understood.