Meaning: This sentence describes the shells on the beach, which seem to be whispering secrets about the deep and mysterious parts of the ocean.
Choice of Words: Shells are the hard outer coverings of certain sea creatures, such as clams and oysters. "Whispered" means to speak softly or in a low voice. "Secrets" are private or confidential information. "Deep" refers to the part of the ocean that is far from the shore and is difficult to reach.