Why does Spain have a different dialect/language than other spanish speaking countries?
No one could really help me answer this at school and its been really making me mad on why that this is! I would LOVE your help!
8 Answers
When groups of speakers of a language are isolated from one another (usually geographically but there can be other barriers) the language drifts in different ways in the different regions. That is, all languages (except dead languages) evolve over time. If all the speakers of the language are in frequent contact, they share the changes (mutually affect one another) but if some groups are isolated (for whatever reason), they tend gradually to go their "separate ways" and this leads to different dialects (and, after enough time, different languages).
The point being made (with a bit of sarcasm) by Culé is that there is no "Latin American" Spanish. Every Spanish speaking country has dialectical differences that distinguish it from every other Spanish speaking country and (except for the smallest countries) regional differences within the country that can be called dialects. Culé was referring to the other countries (excluding Spain) but there is also no such thing as the "Spanish of Spain", either. There are, roughly, half a dozen dialects in Spain (dialects of Spanish, not separate languages such as Basque, Catalan, Gallego, etc.).
Referring to dialects in the U S A, one often hears such gross oversimplifications as "He speaks a southern/northeastern dialect." You may not be able to tell the difference between the speech of someone from Louisiana and Mississippi or between Vermont and New Hampshire or, even, the different boroughs of New York but, to the people who live there, they are different dialects and they can recognize the differences.
Basically, if, after listening to someone speak for several minutes, you are able to say "You're not from around here, are you?", the most likely reason for your saying that is because of dialectical differences. (Based on how they spoke not what they said. Obviously, as a New Yorker, if someone asks me "Where/What is Times Square? or "How do I get to Fifth Avenue?", I conclude that the person is not a local (but that's based on the content of the question). I recognize different dialects not on the basis of what is said but on how it is said.
Wow, hey, what we think is that all those other countries have a different "dialect"
tse,,tse, tse
Why does Colombia have a different dialect/language than other Spanish-speaking countries?
Why does Argentina have a different dialect/language than other Spanish-speaking countries?
Why does Mexico have a different dialect/language than other Spanish-speaking countries?
Why does Panama have a different dialect/language than other Spanish-speaking countries?
Why does the USA have a different dialect/language than other English-speaking countries?
For your information, people speak differently in different countries, and there is a huge diversity in Latin American countries when it comes to Spanish. The distance, obviously, makes Spanish in Spain maybe further apart, but not that different. I speak with a Mexican and an Argentinian friend at least once a week here where I live, and none of us have any problems communicating, and none of us have the feeling that we are speaking different languages.
Why do Boston, Philidelphia, and New York have such different dialects that they are almost mutually unintelligible, yet are only short distances apart?
Wow! Breaking News! All other Spanish speaking countries have the same dialect?!
¡No me lo puedo creer!
I would say that UK English and American English can be grouped. If I were in England, I wouldn't be offended if someone said I spoke American English. I'm comfortable enough with myself and my language that I can accept that generality for what it is: a gross simplification of the differences thousands of miles make in a language. A generalization isn't necessarily a denial of anything -- it's simply what it is: looking at the big picture.
I think most of us are aware that, yes, Spain does have singularities all its own including a lisp and vosotros -- makes learning Castillian Spanish a special challenge all its own. And it IS different from learning "Latin American" Spanish -- I don't think rdog was denying that there might be differences among those dialects. He was pointing out that there are more distinguishable differences between Castillian and Latin American Spanish as groups and he wanted an answer as to why the gross (big picture) differences existed.
The distinction that needs to be made is that Spanish-speaking countries are just that: countries. They're not states in one larger nation with a united identity -- they have their individual national pride, and that pride includes their language and the dialectical differences that distinguish them, make them unique.
OK, we're picking on you because this question is asked almost every other day, and it's very easy to find the answer if you really want to know. Here are a few discussions to reference to, but please feel free to search for yourself. 
¿Por qué no tiene la gente de mi ciudad un acento como el resto del mundo?
