Does your child say key as TEA? Speech and language therapists call this ‘fronting’ because T is said with the tongue tip and K with the back of the tongue. But seldom the other way round. (‘Backing’ is rare.) Children who front when they are small may go on to struggle with longer words with the K sound, and other seemingly unrelated skills, including hearing rhymes.
Rather than treating fronting as a tongue problem, there is a better account by the ‘building’ of the sound. And, yes, sounds are built – starting at the bottom (1), as with a house, with a complete closure somewhere in the vocal tract, then (2) closing off the nose to form a single resonator in the mouth (rather than a double resonator with the mouth AND the nose), then (3) instead of forming the closure at the back of the mouth, forming it at the front with the tongue tip, as the default articulation placement (shown in red here), then (4) setting a pause between the release of the closure and the setting of the vocal cords just far enough apart to vibrate against one another and form the vowel. For each ‘layer’ in the building of the sound there is an icon, also in red. This ‘cognitive’ account of fronting explains why backing is rare and why fronting is often part of a larger problem.