“Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue.”
King James Version (KJV)
14:19 With my understanding - In a rational manner; so as not only to understand myself, but to be understood by others.
1Co 14:19 I had rather speak five words with my understanding, etc. All must be done to edification (see 1Co 14:26). Hence, all must be understood. There is a lesson here to preachers who are so learned in their utterances that the people cannot understand them.