How does David Brin use imagery in Startide Rising?

Imagery:

"Brookida switched to Anglic. Though somewhat shrill and stuttered, it was better than Toshio's Trinary. Dolphins, after all, had been modified by generations of genetic engineering to take up human styles, not the other way around."

"The hairy creature was creating land—or at least a solidity—in a narrow causeway in front of the party! Just before and on both sides of the train, there was a faint shimmering where reality seemed to struggle against a noxious intrusion."