I think your remark is a generalisation. When I first spoke in tongues it was spontaneous, and I have prayed for folk and they have started speaking spontaneously. I have also helped others, and they have spoken clear and beautiful languages quite unexpected when they have used their faith and started speaking. I do think that if someone was coached and all they did was to say "ba ba ba sha ba", etc, then I would say they had not broken through into the genuine gift of tongues. But I have sat people down in a quiet place over a cup of coffee, explained the gift of tongues to them, and then give them my four steps of faith to receive it (know that it is God's will for you; ask for the gift; receive it by faith; launch out and start speaking -activating your faith). These are sound Scriptural steps. Most times when I have laid hands on the person and instructed them to speak out in the Name of Jesus, they have spoken out in their own unique language, expressive and beautiful. God showed me those steps of faith when I saw a crowd of people around some poor soul and half of them were saying "hold on brother" and the other half saying "let go brother". The poor guy didn't know whether to hold on or let go! I said to the Lord, "This isn't right. Show me a better way." and He did, and after that, using the steps of faith He showed me, it worked every time.