Honorifics are a feature of Japanese language that have been creeping into English dubs and which are frequently carried over intact and unannotated in subtitles. Honorifics are the Japanese equivalent of "Mister", "Mrs.", "Doctor" and the like, except that there are far more of them with far more nuances of meaning than there are in English. They are employed as suffixes to names or in some cases ("sensei", for one) as substitutes for names.
Politeness is a critical part of Japanese language and culture, and honorifics are a key element in that. In general they are expressions of respect or endearment, but as with many terms in many languages, delivery — tone and emphasis — can change a title of utmost honor to an insult. Using the wrong honorific, or the right honorific in the wrong way, can result in anything from simple disdain to (in feudal times, at least) clan warfare.
Some honorifics can also be employed as stand-alone words.