Xindi-Aquatic languageedit this page
From Memory Alpha, the free Star Trek reference
The Xindi-Aquatic language is the very complex language used by the Xindi-Aquatics. It consists of high or low pitch hums that are similar to those produced by Terran whales.
The language switches to SONAR when the past tense is used. (ENT: "The Council")
Hoshi Sato said that she thought the Xindi-Insectoid language was difficult while trying to translate an Aquatic message. (ENT: "Damage") Commander Dolim heard the language his entire life, but it never came easily to him. (ENT: "Countdown")
