That is not his point at all. Of course what is said in a language is good - NOTHING WRONG WITH THE CONTENT but it is the PRACTICE of praying a good prayer in a different language without UNDERSTANDING by the one praying and/or the one listening - BOTH are wrong and being condemned.
That is the whole point of this "else" consequence of following the WRONG example in verse 14 and not following the right example in verse 15. IT IS WRONG TO PRAY IN THE SPIRIT by anyone at anytime if edification of the MIND is not included. That is his determined point stated clearly in verse 15. You are taking the "else" condemnation passage and presenting as the example to follow when it is given as the example to be condemned.
12 Even so ye, forasmuch as ye are zealous of spiritual gifts, seek that ye may excel to the edifying of the church.
13 Wherefore let him that speaketh in an unknown tongue pray that he may interpret.
Paul's point - The rule of edification MENTAL UNDERSTANDING applied in verses 6-11 is to be applied to the INDIVIDUAL in verse 13
14 For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful.
Paul's Point - The "if" BAD scenario of not following the MENTAL UNDERSTANDING edification rule is here presented as a NEGATIVE example
15 ¶ What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.
Paul's Point - The Positive determinate example is now stated IN CONTRAST to verse 14 as the proper application of the rule of edification = MENTAL UNDERSTANDING with whatever is done in Spirit.
16 Else when thou shalt bless with the spirit, how shall he that occupieth the room of the unlearned say Amen at thy giving of thanks, seeing he understandeth not what thou sayest?
Paul's Point - "else" is the alternative to obeying the positive determined practice in verse 15. "else" is the CONSEQUENCE of disobeying Paul's positive example in verse 15. "else" is the contrast to obedience to verse 15. If you don't obey verse 15 to practice MENTAL UNDERSTANDING with all you do "in the Spirit" this will be the consequence.
[B]17 For thou verily givest thanks well,[/B]
Paul's Point - The negative consequence is not to be found in the LANGUAGE CONTENT in the spirit. The pray is said good. The negative consequence is that it is not accompanied by MENTAL UNDERSTANDING in both the one praying and the one listening - IT VIOLATES the law of edification and the positive command by example stated in verse 15. The CONTENT of the prayer does not violate it, but the PRACTICE of the prayer without MENTAL comprehension violates it.