Let's start with the basics first, which are not really related to english-these are universal rules.
- A sentence starts with uppercase(yeah, the CAPSLOCK button/holding the SHIFT key has, indeed, a purpose!).
- Comma spacing. There's no space between the first word and the comma and one between the comma and the following word; exempli gratia: "word, word".
- An interrogative sentence ends with a question mark("?")-unless it's a rhetorical one, which could be either an exclamation mark/a mere period/question mark.
Now, that we got that right, let's get to the next level.
English had multiple forms from its beginning till now: Old English, Middle English and (early)Modern English. Keep in mind that these forms had more letters(runes) than the current one(that results in the replacing of, let's say, two different runes with a single letter, hence the existence of homographs.