OMG
As I explained before, it is NOT about the sounds you make. It is about understanding and using the language. Yes, you use your mouth to make spoken language, but the speech sounds are not the entirety of spoken language.
As Grendel said, is moving your hand all that makes up written English? No, it is a piece of it, and if you struggle with it, it will affect your ability to be understood in written form. The same is true with speech. The actual speech sounds you make has some impact on the ability of strangers to understand your spoken language, but it is the the complete story.
For example:
In AV therapy a student is asked, "The stewardess brought the man a hot towel and his meal. Where are they?" The child should answer "On an airplane." The therapist would then know he knows the words meal, and stewardess (his target vocabulary). If the child doesn't know, the therapist could explain "A stewardess is like a waitress but she works on an airplane".
It doesn't matter if the child says "stewardess" or "airplane" with perfect articulation, the focus is on using and understanding the language involved.