A common misconception is that people tend to think Flemish as a separate language. It is in fact not a language, it’s really not even a dialect. In Belgium three languages are spoken (the three official languages of Belgium): in the southern part people speak French, a small part of eastern Belgium speaks German and the northern part of Belgium speaks Dutch or Flemish as some people like to believe.
So the northern part of Belgium is called Flanders. While Flemish is actually Dutch, as it is spoken in Holland (the Netherlands) with only a small difference in accent. Flanders is divided in provinces, we have: Antwerp, Limburg, Flemish-Brabant, West-Flanders and East-Flanders (In Dutch: Antwerpen, Limburg, Vlaams-Brabant, West-Vlaanderen and Oost-Vlaanderen).
Every person in a province speaks a different dialect of the Dutch language, compared to the other provinces.
In Antwerp for example the difference between the dialect and the actual Dutch language is minimum and a difference can barely be noted. In Limburg people are known for the melodious voices, (But still difference is minimum). Now East-and West-Flanders are known for their dialects because (especially West-Flemish people) of the incredibly strong accent. If someone from West-or East-Flanders is interviewed on T.V, subtitles are always required in order for the other inhabitants of Flanders to view the show. This variant is not a separate language. It is merely a difference in accent. And if Dutch people listen carefully all words can be comprehended, even though some things are hard to comprehend even for inhabitants of West-Flanders (in which the dialect is strongest). Singer Flip Kowlier for example, who was a hit among Flanders’ youngsters, was incredibly hard to understand, even for inhabitants of West-Flanders.
Although the dialects in Flanders are different from the main Dutch language, it is a mistake to think it a separate language. And so the language Flemish does not really exist. Even some people in Flanders call it Flemish, they are wrong. :)
Inhabitants of Flanders are called Flemish people though.