ACCENTS
It is one of the many merits of the English language that words and sentences can be made sufficiently intelligible without the aid of accents, which are reserved for dictionaries and educational books. The grave accent for the final syllable -èd occasionally is used in poetry to show that this -ed is a distinct syllable. It rarely appears in prose, but when so marked by an author it should be repeated. All words or proper names distinctively foreign should be carefully accented as they appear in their own language. Other foreign words that have been incorporated in the English language, as depot, debut, debris, etc., do not need accents; but when accents have been carefully added by the writer they should so appear in print.
O AND OH
The forms O and oh are often made interchangeable by some very careful writers; but it seems to be generally conceded that the proper form for an address in the vocative is O, with the exclamation-point at the end of the exclamatory phrase, and not immediately after the interjection.
O Lord, have mercy on us!
O my fellow-citizens!
Break on thy cold gray stones, O sea!
Blessed art thou, O Lord!