In English, we generally use a comma in front of the conjunctions “and” and “or”. The structures in English allow for us to skip the comma when working with other conjunctions. In certain sentences, the pause indicated by the comma will not be enough and a semi-colon must be used instead.
Subordinate adverbial clauses between two conjunctions cannot be preceded by a comma. In lists made up of three or more elements, a comma is normally used before the conjunction that separates the last two terms, especially if the last one is more extensive. In this case, the comma disappears in Spanish.
Before adverbs or circumstantial complements, English makes it easier to omit the comma in order to maintain the continuity of the sentence. In Spanish, if the adverbial or circumstantial elements don’t take up their normal position in the sentence, it is usually preferable to use the comma.
Another common use for the comma in English is between two or more adjectives that are describing the same noun. In Spanish, this form of punctuation has an expressive value.
In English, the comma is also used to introduce a textual quote, whereas a colon is used in Spanish; the comma can also be placed after the quote, if the quote itself was the beginning of the sentence. Unlike Spanish, the comma is placed within the quotation marks in the latter instance, unless the quote contains an exclamation mark, question mark, or another important grammatical aspect that must be included. The same thing happens with the dashes in an aside or clarifying statement within a sentence.