There is one important aspect in all languages: Spellings and this is peril as we have forgotten the art of Correct Spellings. There was a time, a few decades back only when accuracy in spellings was the criteria of being linguistically qualified.
Don't live under the impression that you have understood Parts of Speech and no longer need a look back to the concept. Mastering them means mastering the language; that is tough to declare!
A Proper Understanding of the Punctuation Marks enables Impressive Writing. English Grammar considers these marks as the most significant for Correct Writing. Remember, a Punctuation Mark can
Language comes before Grammar! Grammar is an attempt to describe a language. Hence, the language stands supreme and we as subordinates depend on the grammar of the language to access its virtues and mysticisms.