Punctuation and the comma that points the wrong way
Most marks function as they do in English. A few are visibly mirrored. Some habits are different.
Modern Arabic punctuation is a relatively recent system. Classical Arabic texts had little of it; readers managed with grammar, context, and the rhythm of clauses. The marks now in use were standardised in the late nineteenth and early twentieth centuries, partly under European influence, and they map closely onto the Western set. Several have been mirrored to suit the right-to-left direction of the script. A few have not, and the inconsistency is itself informative.
The comma points the other way
The Arabic comma is ،. It is the same shape as the Western comma, flipped: the tail points up and to the right, where the Latin comma's points down and to the left. The Unicode codepoint is U+060C, distinct from the Latin comma. Functionally it works exactly like a Western comma — separating clauses, listing items, isolating a vocative. The visual mirroring is the only difference.
The Arabic semicolon, ؛, is built on the same principle: same shape as the Latin semicolon, mirrored. The Arabic question mark ؟ is a Latin question mark flipped horizontally — the curl opens to the left rather than to the right. The colon and the period are not mirrored: a colon is a colon, a period is a period. They are symmetrical anyway and the convention is to leave them as they are.
Why mirror some and not others? The mirrored marks are the ones whose visual asymmetry would, when placed on the right end of a phrase in right-to-left text, "point the wrong way." A Latin comma at the end of an Arabic phrase visually leans into the white space rather than back toward the text. The Arabic comma corrects that. A period and a colon look the same either way and do not need correction.
Exclamation marks
The exclamation mark is borrowed wholesale from the Latin alphabet — same shape, same character, same use. It is also, in serious modern Arabic prose, much rarer than in English. Newspapers and literary writing use it sparingly. You see it routinely only in informal contexts and in translated material.
Quotation marks
Three conventions coexist. Latin straight quotes " " are the most common in print, especially in newspapers and on the web. The French guillemets «…» are also very common and are the standard in many literary publishers. Some publications use the Latin curly quotes. There is no single dominant standard — picking up a couple of Arabic novels from different decades and different countries will show you all three. As a designer, the safest choice is to follow whichever convention a given publisher is already using.
Note that when guillemets are used in Arabic, the opening guillemet is « on the right and the closing is » on the left, mirroring French rather than Arabic word order. The bracket-like nature of the guillemets makes them feel symmetrical to the eye even though, in strict directional terms, they are coming from a left-to-right convention.
Brackets, dashes, and dots
Round brackets, square brackets, and curly braces are borrowed unchanged. Like the period, they are symmetric enough that no mirroring is needed. The em-dash and en-dash are used for parenthetical material in literary prose, much as in English, but Arabic prose tends to use them less than English does, preferring commas and semicolons.
The horizontal dot trio ... for ellipsis is the same as in English. Some writers use a single ellipsis character (U+2026) and some type three periods; both are seen.
Spacing and indentation
Modern Arabic typography uses single spaces between words, no special spacing before or after punctuation (so a comma is followed by one space, like in English), and either first-line indentation or a blank line between paragraphs. The choice is style-guide level: most Arabic novels indent paragraphs; web text usually uses blank lines between them; newspapers vary.
Headings and subheadings are conventional. Centred headings are common in religious and traditional contexts; left-aligned headings are common in modern publications. (In RTL contexts, the equivalent of "left-aligned" English headings is right-aligned.) There is no equivalent of the Latin convention of capitalising the first word of a sentence — Arabic has no case distinction at all — so sentences begin without a visual cue beyond the period and space that ended the previous one.
The bismillah
One textual convention deserves a note even though it is not strictly punctuation. Many Arabic books, letters, articles, speeches, and forms begin with the formula بسم الله الرحمن الرحيم — bismi llaahi r-raHmaani r-raHiim, "in the name of God, the Compassionate, the Merciful." It is the opening invocation of the Quran and, beyond its religious meaning, functions as a marker of textual seriousness — the equivalent, very roughly, of starting an English document with a formal opening or epigraph. It is not universal — secular and modernist publications often omit it — but you will see it often enough that recognising it as a textual opener rather than as the first sentence of the text proper is a useful piece of reading literacy.