It is helpful to start with /k/ and once /k/ is mastered at the word level, begin shaping the /k/ into the /g/ sound.
Use a mirror or phone camera to have the child copy your tongue placement for /k/
Use your hand (knuckle side up) and show how the back of the tongue (near the wrist) moves up and back, while the tongue tip (finger nails) goes down
Exaggerate the /k/ sound "kkkkkk"
I call it the crazy car sound
Practice gargling to shape the /g/ sound
Have the child identify words that start with the /k/ and /g/ sound, "which word starts with "k", "car" or "go"?
Start practicing the /g/ sound with words that begin the "gr" like "gorilla" or "grass"- the /r/ helps to facilitate the posterior tongue to move back
Practice growling like animals
Use a tongue depressor to hold the tip of the tongue down
Have the child lay down on the grown to have gravity help pull the back of the tongue down
Tap the back of the tongue and back of the palate to provide sensory awareness *be careful not to stimulate gag reflex*
Have the child feel the puff of air your /k/ sound makes
Model the sound clearly and slowly "k, k, k, k"
Explain where the tongue goes (tip stays down and the back of the tongue goes up to the back of the mouth)
Read books that have the /k, g/ sound in words throughout the book
Explain that the /g/ sound is the /k/ sound with our voice on
We start producing the sounds in isolation, then in syllables, words and so on until the child is using the sound in conversation.
Good luck! I hope this helps!
Contact Speech Language Voice & Swallowing PLLC for a complete articulation evaluation and treatment plan.