Even though it's not the area of linguistics I concentrated on, I've always been fascinated with phonetics -- the sound repertoire of languages. There's more variation in language phonetics than a lot of people realize. The language with the smallest phonemic inventory seems to be Rotokas, spoken on the island of Bougainville (east of Papua-New Guinea), which has only eleven distinct sounds. The Khoisan language ǃXóõ, spoken in parts of Botswana and Namibia, is probably the highest, with around a hundred (depending on how finely you slice them), including twenty or so "click consonants" and four different tones (i.e., speaking a vowel with a rising or a falling tone can change the meaning of the word -- a characteristic it shares with Thai, Mandarin, and Vietnamese, and to a lesser extent, Swedish and Norwegian).
The result is that languages have a characteristic sound pattern that can be picked up even if you don't speak the language. Check out this video from a few years ago, illustrating how American English sounds to a non-English-speaker:
"This study showed for the first time that a non-human brain can distinguish between two languages," said Attila Andics, senior author of the study. "It is exciting, because it reveals that the capacity to learn about the regularities of a language is not uniquely human. Still, we do not know whether this capacity is dogs’ specialty, or general among non-human species. Indeed, it is possible that the brain changes from the tens of thousand years that dogs have been living with humans have made them better language listeners, but this is not necessarily the case. Future studies will have to find this out."