It seems to me that understandable words (or any words at all) are not necessary to worship and that to insist on them is a relatively modern view, even in the pews. Obviously, the didacticism inherent in audience-directed speech can inhibit more immediate appeals to the heart. Hence, some painters refuse to name their paintings and all readers of poetry prefer the poem to its explanation. They insist on the more direct appeal of experience. This seems even truer of the mass, surrounded as it is by depictions of Jesus’ sacrifice and based in centuries of observance. All who see it, and, yes, hear it know what is being elevated at the table and the story spoken over it. If not, the Roman Catholic Church has greater problems than translation would cure. So, what’s going on here?
Many of my most moving prayer moments and experiences have involved "nigunim", chant-like repetitions of traditional religious melodies (mostly of Hasidic origin, reappropriated within the havurah/Jewish renewal world), some with a short, evocative Hebrew phrase (which becomes a form of "mantra"), some wordless, typically creating a powerful mystical union among a community of worshippers, whatever their efficacy in communicating with the divine.
It is sometimes suggested that nigunim have words, when they do, only (or mostly) to help us remember the tunes, which are sacred.
Words, beyond the evocative or imagistic phrase, are all too often a distraction from prayerful intent/devotion (kavanna and d'vekut), even when they do not invite me to proclaim sentiments that I do not believe, and often do not want to make myself try to believe.