Complex sentence: Their language, art and modes of propulsion were claimed to use advanced knowledge of the power of sound, and they were said to be highly telepathic as a result, often resorting to communication with eyes closed and sending evocative images to each other via brain waves.
Split into simpler sentences: Their language, art and modes of propulsion all utilized advanced knowledge of the power of sound. They were highly telepathic as a result, often resorting to communication with eyes closed and sending evocative images to each other via brain waves.