I do not know about you, but I always find the Biblical concept of speaking in tongues hard to understand. I understand it intellectually, but I have never witnessed someone speaking in tongues. So I have a hard time understanding the power of witnessing someone speaking in tongues. Thus today's reading is a difficult one for me, but amazingly enough, as with most (if not all) Biblical readings there are messages that are relevant for all of us, even someone like me who finds speaking in tongues hard to fathom.
Now I can certainly relate to verse 19, "But in the church I would rather speak five intelligible words to instruct others than ten thousand words in a tongue." Again, from my perspective, listening to someone speak a language I cannot understand seems less effective then listening to words I can understand. As examples, when I travel to a country whose native language is not English, I cannot understand people who speak to me in their native language - no matter how loud they speak or how many words they speak. Likewise, in the early Church, when the prayers at worship services were given in Latin as opposed to the native language, I can imagine that this would not be conducive to attracting people to the Church. In the second millennium AD, when the Bible and worship services where translated into local languages this was, in my opinion, an enhancement which brought more people to the Church and to Christ. Having said all of this, I would agree with Paul's comment in verse 19 - understanding the message is critical to it being properly received and accepted.
Paul begins today's reading by saying those that speak in tongues should pray for the gift of interpretation. I fully agree and this, to me, seems obvious. To bring more people to Christ, the calling for all of us, people must understand our message. Delivering this message in a way that is understood by the receiver is critical. This goes beyond speaking a commonly understood language. This means speaking to a young person in language they understand, speaking to a seeker using examples to which they can relate, or speaking to a non-believer with respect and courtesy so we do not put them off from the message we are giving.
Wishing you the best in your walk with Christ,