The N-word gets all the attention. It is one of the ten most sensitive terms in the English language. There appears to be no proper usage of the word in a mixed race audience except by lecturers, black musicians, and comedians unless they get drunk or serious. The African-American Registry, linked here, contains a more complete review of the history and usage of this word. The following are some of my observations.

Used between blacks, it is a term of familiarity, evocative of feelings deriving from common suffering. African-Americans will rarely take offense when another African-American uses the word, but will take offense if the speaker is white. Continued use of the word and its derivatives creates a racially loaded double standard.

Used by whites it is always a slur. When used between whites it is usually ignored but it will often trigger a class-tolerance reaction with the speaker either admitting age or losing status from the admission of lack of education and breeding associated with lower socio-economic status. Its usage is not allowed by whites in the presence of blacks. Use of the word will cause those in earshot to furtively glance around the room to make sure no blacks are present.

Some whites, particularly those with a military background, will maintain that it is not a racial term at all, but merely refers to slackers. The fact that 99.44% of the slackers so named are African-American tends to undermine this hypothesis.

It can be redacted, deleted and otherwise expunged from the record but it is always there. Place names around the country have been changed. Movies edited. Song and book titles have been changed. The list goes on and on. Are we changing history to avoid offense, to reduce reinforcement or for some other reason. Can problems be solved this way?

It has eclipsed other ethnic and racial slurs applied to blacks, Jews, Hispanics, illegals, Italians, Irish and many more in terms of its power to offend. Many of those have just been forgotten. There is something about the relationship between blacks and whites that makes it impossible to forget.

It joins four other English words euphemistically rendered in print by reference to their initial. None of the other four seem to have the social impact of the N-word. Curiously it is not one of George Carlin's seven infamous words.

There are many pronunciations and derived terms. Even innocent words with similar spellings or pronunciations are tainted by proximity. (Compare to "formication" which is the spontaneous sensation of ants crawling on your skin, from formic, the acid ants secrete when they bite.)

Sensitivity to this word and other racial innuendo is intense. When Imus referred to the Rutger's women's basketball team as "tattooed ... nappy-headed ho's" he triggered a reaction that totally undid his career.