When they dive together, sperm whales make patterns of clicks to each other known as "codas." Recent findings suggest that not only do different codas mean different things, but that whales can also tell which member of their community is speaking based on the sound properties of the codas. Just as we can tell our friends apart by the sounds of their voices and the way they pronounce their words, different sperm whales make the same pattern of clicks, but with different accents.

Source: Whales have accents and regional dialects: Biologists interpret the language of sperm whales