The child who cannot make the 'k', 'kh', 'g' and 'gh' sounds, is not placing his tongue in the correct position and is instead substituting them with 't' and 'd'. This makes cake sound like 'tate'. This speech problem is called primary dyslalia and is a very simple problem to correct. It can be overcome in 2 or 3 speech therapy sessions. Please consult a speech therapist.