The comma (,) indicates a brief pause that takes place within the statement. It is used to separate the members of an enumeration, except the ones that are preceded by any of the conjunctions y, e (and), o, u (or)
For example: Es un chico muy reservado, estudioso y de buena familia. (He is a very reserved, studious boy and he comes from a good family.)
Acudió toda la familia: abuelos, padres, hijos, cuñados, etc. (All the family went: grandparents, parents, children, brothers-in-law, etc.)
¿Quieres café, té o un refresco? (Do you want coffee, tea or a refreshment?)
When the elements of the enumeration constitute the subject of the sentence or a verbal complement and go before to the verb, a comma is not placed behind the last one.
For example: El perro, el gato y el ratón son animales mamíferos. (The dog, the cat and the mouse are mammals
De gatos, de ratones y de perros no quiere ni oír hablar (Of cats, mice and dogs he does not even want to hear speak)
The comma is used to separate grammatically equivalent members within a statement, with the exception of those cases in which some of the following conjunctions are found: y, e, (and) ni, (neither) o, u (or)
For example: Estaba preocupado por su familia, por su trabajo, por su salud.(He was worried about his family, his work, his health.)
Antes de irte, corre las cortinas, cierra las ventanas, apaga las luces y echa la llave. (Before you leave, close the curtains, close the windows, turn off the lights and lock the door.)
However, a comma is used in front of the conjunction when the sequence that it precedes expresses a content (consecutive, of time, etc.) different from the previous element or elements.
For example: Pintaron las paredes de la habitación, cambiaron la disposición de los muebles, y quedaron encantados. (They painted the walls of the room, they changed the disposition of the furniture, and they were enchanted.)
Also when that conjunction is to be connected with the entire previous statement, and not with the last one of its members.
For example: Pagó el traje, el bolso y los zapatos, y salió de la tienda. (She paid for the dress, the purse and the shoes, and left the store.)
Finally, its use will always be advisable when the period is especially long.
For example: Los instrumentos de precisión comenzaron a perder su exactitud a causa de la tormenta, y resultaron inútiles al poco tiempo. (The precision instruments began to lose their precision because of the storm, and were useless soon after.)
In a relation whose elements are separated by a semicolon, the last element, in front of which the copulative conjunction appears, goes preceded by a comma or semicolon.
For example: En el armario colocó la vajilla; en el cajón, los cubiertos; en los estantes, los vasos, y los alimentos, en la despensa. (He placed the dishes in the cupboard; the silverware, in the drawer; the glasses in the shelves, and the food in the pantry.)
With great seriousness, he said to his family that he would arrive at three; to his friends, to wait for him at five; and he was able to be on time on both cases.
A comma is written to separate the vocative from the rest of the sentence.
For example: Julio, ven acá. (Julio, come here.)
He dicho que me escuchéis, muchachos. (I have told you to listen to me, boys.)
When the vocative goes in the middle of the statement, it is written between two commas.
For example: Estoy alegre, Isabel, por el regalo. (I am happy, Isabel, with the gift.)
The clauses that break a sentence, either to clarify or develop what is being said, or to mention the author or work quoted, are written between commas.
The following cases are considered clauses:
a) Explanatory appositions.
For example: En ese momento Adrián, el marido de mi hermana, dijo que nos ayudaría. (At that moment Adrián, my sister’s husband, said that he would help us.)
b) Explanatory adjective propositions.
For example: Los vientos del Sur, que en aquellas abrasadas regiones son muy frecuentes, incomodan a los viajeros. (The winds of the South, that are very frequent in those hot regions, cause discomfort to the travelers.
c) Any comment, explanation or precision to something said.
Examples: Toda mi familia, incluido mi hermano, estaba de acuerdo. (All my family, including my brother, agreed.)
Ella es, entre mis amigas, la más querida. (She is, among my friends, the most cherished.)
Nos proporcionó, después de tantos disgustos, una gran alegría. (She gave us, after so many dissatisfactions, a great joy.)
d) Mentioning an author or work that are quoted.
For example: La verdad, escribe un político, se ha de sustentar con razones y autoridades. (The truth, writes a politician, has to be sustained with reasons and authorities.)
When the regular order of the parts of a statement is reversed, placing in front elements that usually go behind, there is a tendency to place a comma after the group that has been placed in front. It is not easy to establish exactly the cases in which this anteposition demands the use of the comma. But frequently this practical norm can be applied:
a) If the element placed in front admits a paraphrase with "as far as", it is preferable to use a comma.
For example: Dinero, ya no le queda. (Money, he has nothing left.) (It is possible to say En cuanto al dinero, ya no le queda (As far as the money goes, he has nothing left)).
b) If, on the contrary, it admits a paraphrase with "is what" or "is which", a comma will not be used.
For example: Vergüenza debería darte. (You should be ashamed.) (Equivalent to Vergüenza es lo que debería darte (Ashamed is what you should be)).
Also, a comma is usually placed in front of a conjunction or conjunctive locution that links the propositions of a composed sentence, in the following cases:
a) In the adversative coordinated propositions introduced by conjunctions like only, but, although, if not.
For example: Puedes llevarte mi cámara de fotos, pero ten mucho cuidado. (You can take my camera, but be very careful.)
Cogieron muchas cerezas, aunque todas picadas por los pájaros. (They took many cherries, although all bitten by the birds.)
b) In front of the consecutive propositions introduced by so then, so, so that...
For example: Prometiste acompañarle, conque ya puedes ir poniéndote el abrigo. (You promised to go with him, so you can already start wearing your coat.)
El sol me está dando en la cara, así que tendré que cambiarme de asiento. (I’m getting the sun on the face, so I will have to change to another seat.)
c) In front of logical and explanatory causal propositions.
For example: Es noble, porque tiene un palacio. (He is a nobleman, because he has a palace.)
Están en casa, pues tienen la luz encendida. (They are at home, because they have the lights on.)
The connections such as esto es, es decir, o sea, en fin, por último, por consiguiente, sin embargo, no obstante, además, en tal caso, por lo tanto, en cambio, en primer lugar (this is, that is to say, that is, in short, finally, therefore, nevertheless, however, in addition, in such case, hence, however, in the first place), and also, sometimes, certain adverbs or locutions that perform the function of sentence modifiers, like generalmente, posiblemente, efectivamente, finalmente, en definitiva, por regla general, quizás (generally, possibly, indeed, finally, really, as a rule, perhaps), placed at the beginning of a sentence, are separated from the rest by means of a comma.
For example: Por consiguiente, no vamos a tomar ninguna resolución precipitada. (Therefore, we are not going to take any hasty resolution.)
No obstante, es necesario reformar el estatuto. (However, it is necessary to reform the statute.)
Efectivamente, tienes razón. (Indeed, you are right.)
When these expressions go in the middle of the sentence, they are written between commas.
For example: Estas dos palabras son sinónimos, es decir, significan lo mismo. (These two words are synonymous, that is to say, they mean the same.)
Tales incidentes, sin embargo, no se repitieron. (Such incidents, nevertheless, were not repeated.)
Este tipo de accidentes son causados, generalmente, por errores humanos. (This type of accidents is caused, generally, by human errors.)
If the blocks that are linked by these connections form the same compound sentence written between periods, a semicolon placed in front of the connection, which will be followed by a comma, usually separates them.
In the cases in which a verb is omitted, because it has been previously mentioned or because it is understood, a comma is written in its place.
For example: El árbol perdió sus hojas; el viejo, su sonrisa. (The tree lost its leaves; the old man, his smile.
Los niños, por aquella puerta. (The children, through that door.)
En matemáticas, un genio; para la música, bastante mediocre. (In mathematics, a genius; with music, quite mediocre.)
On the headings of letters, a comma is written between the place and the date.
For example: Guadalajara, Jalisco, 25 de enero de 2000. (Guadalajara, Jalisco, January 25, 2000.)
A comma is written to separate the inverted terms of the complete name of a person or those of a syntagma that integrates a list (bibliography, index...).
For example: BELLO, Andrés: Gramática de la lengua castellana destinada al uso de los americanos. (BELLO, Andrés: Castilian Language Grammar destined to the use of Americans.)
CUERVO, Rufino José: Diccionario de construcción y régimen de la lengua castellana. (CUERVO, Rufino José: Dictionary of construction and regime of the Castilian language.
· construcción, materiales de (construction, materials of )
· papelería, artículos de (stationery, items of)
Incorrect use of the comma
The subject and the predicate MUST NOT be separated by a comma.
Examples of incorrectness.
*Las estanterías del rincón, estaban perfectamente organizadas. (* The bookcases on the corner, were perfectly organized.)
*Un desgraciado incidente, ocasionó la dimisión de la junta directiva. (* An unfortunate incident, caused the resignation of the board of directors.)
The cases in which a clause between subject and the predicate exist, as we have already seen, are an exception.
For example: La medicina preventiva, como ya ha quedado apuntado anteriormente, permitirá evitar la enfermedad en breve plazo. (Preventive medicine, as it has already been outlined above, will allow to avoid the disease in a short time.)
La presencia de la protagonista de la película, que vestía un espectacular traje de noche, produjo muy diferentes comentarios. (The presence of the leading actor of the film, who was wearing a spectacular night dress, produced very diverse comments.)