"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." (1 Corinthians 14:19)
If leaving spoken tongues in the church undeciphered was not a good idea, then why would it have been reasonable for the Church of Rome to conduct all its worship services in Latin? Why were they all conducted in a language that virtually nobody could understand in the first place?
No spiritual edification can take place in the midst of confusion. Even though the Mass no longer has to be spoken in Latin, this custom is implicitly erroneous by biblical standards.