No matter how good a job a translator does, there will also be something lost in translation. While I personally feel that Viz has done quite a respectable job translating the series, there are things that are simply untranslatable. Ranma ½ was released in English prior to the practice of using editors notes to throughly explain some of the untranslatable contepts, so I hope to provide some insight into these unique aspects of the series.
to Ranma ½
Throughout Japan various dialects are spoken. Tokyo is the most common and is what is taught to foreign language students. This is considered the "default" dialect of spoken Japanese.
Ukyo has one of the most obviously different dialects which is known as the Kansai dialect (Kansai-ben). Kansai-ben (a dialect spoken around Kinki district such as Osaka and Kobe so on), is the Japanese equivalent of an American speaking with a Southern accent. For instance usually one would use "inai" for "not there (living being)" whereas Ukyo would say "Orahen". "Oru" is the humble of "iru".
Chinese speakers of Japanese, such as Shampoo, are usually indicated by using "aru" rather than "iru". "Aru" and "iru" both mean "to exist". "Aru" is used with non-living objects such as boxes or pencils whereas "iru" is used with living things such as animals and people. Shampoo uses "aru" all of the time, and she uses it incorrectly, hence her poor grasp of the Japanese language.
Mousse, by contrast, speaks in the Tohoku dialect (Tohoku-ben). According to Wikipedia this dialect has the connotation of being "slow and clumsy and indicates idleness".
The Japanese language doesn't use pronouns as often as they are found in English. That is why a character like Mikado may never have used a "you" in his entire appearance. Usually a person is addressed by their name, or an "understood you" is used instead.
English has almost no equivalent of these Japanese suffixes, so some explaination is required.
-san is probably the most common piece of Japanese any non-speaker would know. Most think it is "mister" or "miss" which isn't necessarily true. It is used to show a comfortable seperation between two people that aren't necessarily close friends. Not using -san after a name implies a certain familarity with that person. When Kuno says Akane-kun he is definitely implying a sort of intimacy in their relationship, -kun being more familiar than -san. Also when a man addresses a women in private by her first name without a -san, or other ending, that also implies that they have an intimate relationship. However, in Ranma's case he doesn't use -san or any other ending when addressing the girls due to his very informal and macho nature.
-kun is commonly used among school children towards those who are in a lower grade than they are, or to indicate a certain level of familiarity, perhaps an acquaintance rather than a best friend. It is also used by teachers when talking to students. It's is most commonly used with males, but can be used with girls too, as Kuno sometimes calls Akane, "Akane-kun".
-chan is an ending that is used to show affection. It is commonly attatched to the names of little children, and also used with girls names. It is sometimes used with boy's names as well, such as when Ukyo calls Ranma "Ran-chan" (translated as "Ranma Honey").
-sama is an honorific ending that can be added after any name to show deep respect.
-sempai is translated as "Upperclassman". Kuno prefers to be addressed this way to show his seniority. The opposite of sempai would be kohai, one's junior or underclassman.
Familiarity isn't necessarily established with -san. Usually you use the last name +san, but since the characters in Ranma ½ are all young people who are relatively friendly they refer to each other by their first names plus -san or they drop the -san to express familarity (Kasumi calling Akane "Akane" with no suffix for instance).
When Ranma does it with Akane, or when Mousse does it with Akane for that matter, it displays their "social ignorance" to a certain extent. Maybe a better term would be "tactlessness" or "lack of social consciousness". By contrast Ryoga always addresses Akane as "Akane-san", indicating a certain distance Ryoga feels he must keep between them, while Akane addresses him as "Ryoga-kun" indicating she feels comfortable treating him as a good friend.
So here's the heirarchy... we'll use Akane as an example. Here's how people might address her.
Tendo-san----- first meeting
Akane-san----- friend/you see Akane often/classmate
Akane--------- engaged or being overly familiar
Another example would be Ranma calling Kuno "Kuno Sempai" (Upperclassman Kuno). This is a respectful term, but Ranma uses it sarcastically.
In Japanese, Kodachi's language is a work of art. When you begin learning the ultra formal speech in Japanese class, you will fully appreciate Kodachi's choice of words. She uses her words to show just how high her standing is in society (self-perceived). Usually, the higher up one goes in society, the more formal their language becomes. It is out of humility that they do this, but the funny part is that Kodachi's actions and choice of words clash. Humility is not a word to describe Kodachi, nor her brother for that matter.
As far as Konatsu's speech, he tends to be very formal. In part because he's playing the role of a girl, and in part because he loves Ukyo (hence the reason he addresses her as "Ukyo-sama"). His speech tends to be formal when he's at his most informal. He commonly uses "Watashi" for I, and, as stated earlier, uses -sama when he's addressing Ukyo. In addition, he addresses his mother as "Hahaue" ("haha" = mother, "ue" = above), and his sisters as "Aneue" ("ane" = older sister, "ue" = above). Thus, not only is his speech honorific (praising and raising the status of the other person) nor only is it humble (lowering one's own status), but it is actually both simultaneously.