Most sounds are grouped in pairs where one sound is made
with the voice turned on and the other sound is voiceless.
The /p/ and /b/ are examples. These sounds are made by putting your two lips together, keeping them together as your teeth open slightly while the airflow is stopped, then opening your lips to release the airflow is a small puff. The /p/ sound is produced with a bigger puff of air than with the /b/ sound. Both are produced in the front of the mouth with the lips and tongue in the same place, but differing in voicing (vibration of the vocal folds) with the /p/ being unvoiced (with your voice turned off and just air passing through your mouth) and the /b/ being voiced (with your voice turned on).
It’s recommended that students practice correcting their speech error at the isolation level for each sound. Move on to the syllable level when 80% mastery is achieved. After that, move to the word level once 80% mastery at the syllable level is reached. The word level is more complex with the sound being practiced at the initial position of words (at the beginning), in the final position of words (at the end) and finally, in the medial position of words (in the middle of words). After achieving mastery of the sound in words, move to the phrase level, then to short repetitive sentences, and finally to longer, more complex sentences as the student masters each level. Finally, reading stories aloud along with structured conversational activities will help the student move to the ultimate goal of correct production during conversational speech.