English is not one language. It’s a collection of dialects. Dialects differ according to grammar, vocabulary, and pronunciation. In every country in which English the first language—England, Australia, New Zealand, the Bahamas, Canada, the United States, etc.—more than one dialect is spoken, but only one dialect is recognized as the standard dialect.
The standard dialect in the United States is called “Standard American English (SAE).” It is not superior to other American dialects as a medium of speech, but it is the dialect used by professional people when conducting business. It is the dialect used in government, scientific research, education, and international commerce.
No matter what dialect you speak at home, if you want to succeed and advance in school and in the workplace, you will learn to speak and write Standard American English

Standard American English
The difference between grammar and usage
The difference between accent and dialect
Standing up to Grammar Bullies