ACCENT AND DIALECT

     There are two possibilities here. The first concerns accent and the second concerns DIALECT. You might be having problems understanding someone because the accent is very strange to you; and you might be having further problems for reasons of dialect.'Dialect' involves more than just pronounciation. It involves grammar as well. The person speaking to you may be using words you aren't familiar with: the vocabulary or lexis may be different. So, if the dialect is very strong-and strange to you-you will certainly have a serious problem.
This doesn't mean that a foreign sounding dialect of English is, in fact, a foreign language. It isn't. A dialect is a dialect of a particular language. It's related to a parent language. Some of the rules are different, but they aren't different enough for the dialect to be considered a completely different language. When the difference is purely one of accent-saying "but" to rhyme with "foot" in English, for example-things aren't too difficult. But when the order of words, or the actual words used are also different, then we are dealing with a dialect rather than just an accent.
     We call the study of sounds in a language phonetics, and a special alphabet, called the phonetic alphabet, has been devised. If you've ever seen It-and you can find It used in good dictionaries-you'll see that It looks rather different from the ordinary English alphabet. It's not necessary to learn this alphabets, though it can be learned quite easily.
     The point is that it allows people to write down exactly how a word is said, so that other people who know the phonetic alphabet can say the word.

TENSES

     A sentence we would not expect to Read in English would be: "I saw him tomorrow." And you could give two explanations. You could say that "Tomorrow" should be changed to something like "Yesterday" or "last week";or that "saw" should be changed to "will see". These are yet more rules of English, and they concern the relationship between the tense of a verb and related adverbs.
     By now, you may have noticed that when we talk about rules, we often mean making things agree with each other.
We have to do the right thing, otherwise there will be chaos. But rather than reffering to These matters as 'rules' ,It is sometimes easier to see them as 'costoms'.
     But when we talk about the customary way of speaking a language we're not Just talking about grammar: we're also talking about pronunciation, for example. When you listen to speakers of English on television, you can usually understand the people who speak like your English teachers, but others are very difficult to understand.

SYNTAX

     There are other rules, too. If I write "cars  blue" instead of "blue cars" you will immediately point out that the words are in the wrong order. The Same would apply to "field in a under sky grass blue a cows". You can, after a struggle,decide what those words say, but in order to solve the problem you have to put the words Into the right order.
There are rules to do with the order of words in English (rules of syntax) Just as there are rules concerning the order of letters in a word.
     Although the order of letters in a word in English remains the same, the actual letters in a word may change. Take the word "house", for example. You know very well that if I write "six house" I am making a mistake. I am breaking one of the rules of English. In order to make what I write correct, I have to put an "s" on the word "house". That is one of the grammar rules of English. It's known as a rule of inflection
     But what about "Houses is nice to live in"? You know that I mean more than one house because I've put an"s" on the word "house", but you are not satisfied with the word "is". You are quite sure It should be "are". Another of the rules of English grammar is that we have to change "is" to "are" when we are talking about more than one thing.
We call that aggreement or concord.

Basics In Grammar

     This is a complete system which makes one language different from another.
We know that German is different from French,for example. They sound different and, on page, they look different. What makes them different is a matter of Grammar. Their grammars are different.
      It has been helpfully said that languages are 'rule governed'. That means that we can't Just make them up anyhow and do what we like when we speak or write them.
If we want to know or check the way a word should be spelt, we can either look It up in a dictionary or Use a computer spellchecker. And we can be confident that the spelling of the word will Stay the Same.