Substituting Fp for F in Initial Position

By Pam Marshalla

boy pucker raspberryQ: My client substitutes fp/f in the initial position, so he says “fpour” for “four”. Why does he put that P in there and how can I get him to stop it?

I have seen this error a thousand times as it is a very common one in young children. Here’s how I see it: The client can say F, but he cannot transition from the voiceless F to the voiced vowel without stopping his airflow. In other words, he has to stop his airflow in order to turn on his voice.

Think of initial F as developing in a sequence: First it starts out as P, then the client adds frication and it becomes FP, then the occluded element is dropped and it becomes F.

We see the same thing with basically all the voiceless fricated sounds. For example, S often starts as T, then it becomes TS, and then it becomes S.

In fact, this is so common that most therapists use T as a way to stimulate S to emerge. We teach a child to say “soap” and we don’t mind if he says “toap” for a while. Also, if he has a lateral or frontal lisp, we often begin the re-training of tongue position for S by working on T.

There are several ways to help your client with his F problem, and here are four ideas to get you going––


First, switch gears and work on clusters for a while. If he can do Fricative + Stop + Vowel (as in “fpour” for “four”), then he should be able to do initial clusters like Sp, St, Sk and so forth. So stop working on F and start working on clusters. He is wearing a sign that says, “I can produce voiceless fricated sounds at the beginning of words only if I can stop the air to initiate the voice.” Thus, go to where he is functioning, and stop working on things that are at a level he has not reached yet.

Airflow, Voice On/Off

Second, work on airflow and voice itself.  Teach him to turn his voice on and off while keeping the airflow going by working on sequences of voiced and voiceless cognate pairs. Tell him “Keep the air going” and “Don’t stop the air.” That way he will be learning how to turn his voice on without stopping the air. Work on these sequences, and then go back to your target words and tell him the same thing, “Don’t stop the air.” Consonant sequences like the following keep the oral posture the same while the voice turns on and off. This makes it a simpler task than sequencing from a C to a V.

  • F-V-F-V-F-V-F-V…
  • S-Z-S-Z-S-Z-S-Z…
  • Sh-Zh-Sh-Zh-Sh-Zh…

Auditory Discrimination Training and Minimal Pairs

Next, model “Fat” as “FPat” and as “Fat” and teach him to hear the difference between the two. Which one is correct? Which one is funny? Should I say, “The bunny is fpat” or “The bunny is fat”? Is my crayon “fpat” or “fat”? What do most kids say?

Visual Understanding


Finally, get him in front of a mirror and teach him the basic difference between F and P. Teach him that he is producing F and P together instead of F alone.


2 thoughts on “Substituting Fp for F in Initial Position”

  1. As an alternative, I have inserted an /h/ in between the fricative and the rest of the word in order to extinguish the production of the stop. At first I separate the fricative and the rest of the word, for example: ffff….hat, sss….hoap, sh….hip. Once the child can do this, I reduce and eventually eliminate the space between the fricative and the rest of the word, but keep a slight /h/ in the word. The /h/ replaces the stop they were using and easily disappears. Sometimes I have to exaggerate the /h/ telling the child to use their “soft air sound” /h/ after the /f/, /s/ or /sh/. It has always worked to achieve the production of /f, s, sh/ without interference of the various stops.

    1. Karin Kouvelas’ method described above is one of the most common found in the old arctic literature. I am sorry I left it off my list of suggestions. An oversight.

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