I'm taking Japanese classes and one thing about the language that I find really unique to Japanese and most other Asian languages is how people can have very distinct speech patterns and say the same thing in a completely different way. There is variety in english and western languages as well, but I find more so in Japanese. This allows for anime to give characters very distinct personalities by changing the way they talk.
Another thing different between Japanese and English are the various levels of formality available in Japanese. How one refers to oneself, whether using the dictionary or polite forms of verbs, omitting articles and desu (to be) at the end of sentences, and word choice; these all affect how polite or rude you sound, and depending on who you are talking to, it can be extremely offensive (talking too informally with someone you don't know very well or with someone with a higher standing than yours -your boss, your teacher, your parents etc) or over-the-top formal and weird (being too formal with your friends can often indicate that you are trying to distance yourself from them)
One Piece relies on these speech patterns for alot of things: puns and other forms of humor as well as personality traits to name just two.
Luffy: He uses "ore" when referring to himself, a very masculine, very informal (sometimes rude even) way to mean "I" "me" or "my." He also uses "da" instead of "desu" (to be) which is another informal method of speaking, not to mention he calls everyone that appears more than a few years older than himself "ossan" or "baasan" (old man or old lady). to speak like this in Japan today would alienate yourself to most adults, as well as a good number of teens and children. Basically Luffy is a rude jerk when he talks XD
Not to mention the rest of the crew, minus Robin and sometimes Sanji (when adressing any female XD). Zoro and Sanji frequently use "Teme" and "omae" when talking to each other and to people they're annoyed at (once again, usually each other) as well as their opponents. These are very rude way of addressing someone you are talking to, (which is already slightly offensive to not use the person's name anyways) and this is why in many subs these are translated to things like "hey bastard" or "you asshole" etc.
Usopp often refers to himself as Usopp-sama… adding any suffix onto your own name (-san, -chan, -sensei) is rude because it places yourself at a higher level than your audience... -sama is reserved for someone of great authority or respect, such as the emperor or head of a company etc. Referring to yourself as -sama is EXTREMELY snooty and rude (Remember how Vegeta always calls himself Vegeta-sama? Know how he's a stuck-up prick? Yeah XD)
Robin is the complete opposite of the rest of the crew, this is due to her background (being polite indicates distance, and Robin had a need for this in the past). She uses the polite verb endings (-masu, masen, mashita etc), and refers to everyone as -san or -kun (navigator-san, cook-san, long nose-kun, doctor-san, swordsman-san, and captain), as she becomes closer to the rest of the strawhats she begins to use their names.
Many other characters have various intricacies about how they talk as well
Kaku: Luffy calls him an ossan and he gets offended, saying he's just in his early twenties. To this, Luffy replies "well you talk like an ossan," indicating that the way Kaku talks is formal and not used very often in modern-Japanese, but older people may still talk in this fashion. Also, during the fight with Zoro, Zoro calls him a "kirin-jaa" (giraffe jar), and Kaku tells him he is a giraffe, not a giraffe jar. However, if you listen to the japanese of what he says, when Kaku says "I'm a giraffe" (kirin da), he actually says "kirin ja" because the way he talks, he says "ja" instead of "da" (to be), so he gets angry because Zoro is making fun of him for how he talks as well as for being a giraffe.
But despite all these various patterns of speech, people are still able to understand each other. In fact, they can add layers to what they say in a way that English speakers cannot.
I had a discussion with a friend about this recently and found it really interesting so I thought I'd share ^_^
What other characters have interesting ways of talking that y'all have noticed?