9 Just so it is with you; if you in the [unknown] tongue speak words that are not intelligible, how will anyone understand what you are saying? For you will be talking into empty space!
10 There are, I suppose, all these many [to us unknown] tongues in the world [somewhere], and none is destitute of [its own power of] expression and meaning.
11 But if I do not know the force and significance of the speech (language), I shall seem to be a foreigner to the one who speaks [to me], and the speaker who addresses [me] will seem a foreigner to me.
12 So it is with yourselves; since you are so eager and ambitious to possess spiritual endowments and manifestations of the [Holy] Spirit, [concentrate on] striving to excel and to abound [in them] in ways that will build up the church.
13 Therefore, the person who speaks in an [unknown] tongue should pray [for the power] to interpret and explain what he says.
14 For if I pray in an [unknown] tongue, my spirit [by the Holy Spirit within me] prays, but my mind is unproductive [it bears no fruit and helps nobody].
15 Then what am I to do? I will pray with my spirit [by the Holy Spirit that is within me], but I will also pray [intelligently] with my mind and understanding; I will sing with my spirit [by the Holy Spirit that is within me], but I will sing [intelligently] with my mind and understanding also.