An educated person will have all four levels of speech.
The more highly educated they are, the higher up the scale their language capacity will go, though they may not be familiar with some of the argot of the lower levels.
Of course, all four levels are language, but that is possible because "language" has two meanings: a generalized, abstract sense that comprises all human speech and writing, and the officially recognized speech and writing of a nation / country / gens — a politically united group of people.
A topolect is the speech / writing of the people living in a certain place or area. It is geographically determined.
A dialect is a distinctive form / style / pronunciation / accent shared by two or more people. To qualify as the speaker of a particular dialect, one must possess a pattern of speech, a lect, that is intelligible to others who speak the same dialect. As we say in Mandarin, it's a question of whether what you speak is jiǎng dé tōng 講得通 ("mutually intelligible") or jiǎng bùtōng 講不通 ("mutually unintelligible"). If what two people are speaking is jiǎng bùtōng 講不通 ("mutually unintelligible"), then they're not speaking the same dialect.
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