How far do we take this? The purpose of a language is communication. If the communication is clear and concise does it really matter if we follow the rules of grammar and spelling to the extreme? Languages change. Any language which does not change dies. The English language has changed and adapted to new forms throughout its history, should we not encourage this evolution?
As for other people who do not speak English, isn't that what made America the great country it is? Peolple from all over the world were welcomed and they brought with them their culture, traditions and language, and over time learned the ways of the earlier immigrants who were now considered Americans. If fully assimilating into the English-speaking American culture is necessary for their success and survival, they will. If they do not need to, they won't.
Lots of other countries in the world have populations who speak many of different languages, and they get along just fine! Even multiple official languages are common. Belgium has three official languages and about 10 others, India 23, Switzerland 4, Canada 2, the list goes on.
As an aside, even some of the posts in this thread have grammatical and spelling errors, but the meanings are perfectly clear. Isn't that enough?
BTW, the word "English" starts with an upper case "e".