Language should flow. As we express our thoughts, ideally the thoughts should not have to wait for the words (unless the subject matter is in some wise "touchy" and we must accordingly be especially careful of our words). Therefore, most people speak in their common language - the jargon of their peers. "How're ya gittin' along?" would be an example. We do not think about the precise manner of expression, as long as the words are sufficient to get across the thoughts we intend. In everyday affairs, the matters facing us are not ticklish enough that we must be overly picky about our speech.
HOWEVER, every man ought to know how to express himself precisely. Notice that I said "precisely," and not necessarily correctly. Grammar and syntax are fashion; they are not science. However, there are times when it does matter how things are said. "I told him he ought to get his car fixed yesterday." "I told him yesterday that he ought to get his car fixed." It makes a difference in the meaning where the "yesterday" is inserted, doesn't it? So, whether or not a man's language is elegant and fashionable, it needs to be accurate. Every man needs to know how to say what he intends to say, and the man who never gives thought to his speech will not know that.
God, in His infinite goodness, gave men the ability to express ourselves beautifully, as well as accurately. Anyone who has read the great speeches of Winston Churchill from 1940, or the poem, "She Walks In Beauty," by Lord Byron, has some idea of how language can be used with consummate skill to express beautifully the things that need to be said. It is good and necessary to be accurate in our speech; it is better also to be beautiful in our mode of expression - at least from time to time. Anyone who uses the King James Version of the Bible ought to have an appreciation for the fact that it is important how things are said, and not only what is said. The ultimate goal of language is that it be true, and also be lovely.