General

Scientists of any department like to give order to the data flood they are facing and discovering. The ISO 639 provides a list with 

Codes for the Representation of Names of Languages

You can find the current list on: 
http://www.loc.gov/standards/iso639-2/php/code_list.php

Categories and classifications are like well ordered drawers in a filing cabinet. When you are a collector the order will help you to find items again. To some extent we all do that with our experiences and discoveries. We give them a place in our personal order. To give structure to the whole thing you simply put more important items on a better place and less valuable on a worse. The order might be constructed simply by our gut feeling. Should we favor an objective approach we will do more or less like scientists. Whatever side is dominating our personal ways when it comes to action we will make a decision based on the data we have stored and the quality of the order. That may lead to a very structured life and provide the feeling of some security in a permanently changing environment. Only when an additional objective view on the current situation is missing and the person is merely reacting on some recognized signals or strict judgments predeveloped from former experiences, the order might to turn out more restricting and limiting than useful. In Standard German they use the word "Schubladendenken", in Standaardnederlands "hokjesdenken" - thinking in boxes - with a negative touch.

Thinking of languages there is the ISO 639 order.  It provides the official names of languages in a list. If  you speak an idiom that is not significantly named in that list you are speaking a dialect - something subordinate. Depending on your state of mind even something inferior. And now?

And now you can say: OK. I have known this before. A dialect one talks in a private circle. The standard language is for all other purposes. 

Or you say: I do not talk any dialect because I am an educated person. Dialects are only for inferior members of the society.

Or: There are so many dialects. One needs a standard language to be able to talk to each other in a larger region.

Or: Despite what it says there my idiom is a language and I feel discriminated. 

Or: Ok. What I speak is not in the ISO 639 list with the official representation of language names. Nevertheless it is part of my personal (and/or cultural) identity. I use it as long as I am with people who are able to understand it.

So what you make of the information stored in the list is entirely your decision. I am a person that loves diversification. Deeply interested in human nature and all its aspects I am curious about different personalities and different ways of life. The "language" we are using is part of that. Learning more about how a conversation partner expresses himself in the context of his origin and current surroundings helps developing a deeper understanding.