After Voyager received a message from this species, Captain Kathryn Janeway attempted to translate the language by instructing the computer to assign symbols to all the different tones in it, hoping to ascertain their meaning. There were over 10,000 different sounds in only one section of the message. In the end, the language proved indecipherable, its complexity far beyond the capabilities of the Federation to translate at the time of the encounter.
However, The cytoplasmic lifeforms could understand the Starfleet crew, probably through the use of a universal translator. It is unknown whether they understood the crew through the use of the Federation universal translator or a similar device of their own.