Me dicen

Me llamo Paco pero me dicen Pato. My name is Paco but everybody calls me Pato (duck).

During my first extended visit to Mexico, I went to a party and talked to a guy who had introduced himself as Salvador. The next day I ran into a mutual friend who had also been at the party. He mentioned that he saw me talking to Chava. I had recently learned that chava means girl, and I told him that I hadn't talked to a chava at the party. He laughed and set me straight: Chava is a familiar version of Salvador, a man's name.

Just as in English, where we can say Bob for Robert or Sue for Susan, many names in Spanish have standard variants. These nicknames (technicallly, hypocorisms/hipocorísticos) are sometimes referred to as diminutivos, even though only some of them are formed by adding a diminutive suffix: Miguel becomes Miguelito. Others are formed by chopping off the end (or the beginning) of the name: Mauricio becomes Mau, Fernando/a becomes Fer, Victor becomes Vic, Guadalupe becomes Lupita. And some, like Chava for Salvador, are more obscure.

It is helpful to be prepared for the most common nicknames.

Nicknames in Spanish

Name Nickname
Alberto, Roberto Beto
Alfonso Poncho
Antonio Toño
Dolores Lola
Eduardo Lalo
Francisco Paco, Pancho
Guadalupe Lupe
Guillermo Memo
Isabel Chabela
Jesús Chuy, Chucho
José Pepe
María Eugenia Maru
Ignacio Nacho

People with two nombres can use nicknames for both: José Antonio becomes Pepe Toño.

As you can see from my anecdote above, many people will introduce themselves with their given name (their nombre de pila) rather than with the name you'll hear later. If you don't know the standard name-nickname associations, you can easily get lost.

If you don't know whether someone uses a nickname, you can always ask: Oye, ¿te dicen Lalo? ¿O prefieres que te digan Eduardo?

Me dicen Lalo

Consider this conversational exchange.

From this example, you can see that llamar is used for the name and decir is used for the nickname. Note that decir, not llamar, translates as call here.

Ser is also possible: Me llamo ______ pero soy ______ para los cuates. (telenovela dialogue)

For talking about nicknames, decir is used: A los Guillermos les dicen Memo.

Apodos

The terms apodo and sobrenombre normally describe some physical or psychological trait. El Greñitas might stick for a little kid with crazy hair. Gangsters and celebrities often get apodos as well: El Chapo (from chaparro, shortie), La Tigresa (the tigress). Note the use of the definite article.

Nombres de cariño

A nombre de cariño is a pet name you call your lover: (mi) amor, (mi) vida, cosita, gordito/a, flaco/a, nene/a (baby), peque (from pequeño, child). Confusingly, the nombre de cariño doesn't always describe the person physically. No te vayas, gorda could be said affectionately to a woman by her parter, even if she is not, in fact, gorda.

La Chabela

To show either affection or contempt, the definite article can be used before a person's name or nickname when you are referring to them in the third person: Ayer me vi con la Tatis (from Tatiana). However, not everyone does this, so observe first whether this usage is common within your social circle before trying it out.

Naming a baby

For talking about naming a baby, the verb you want is poner.

Women's names ending in o

As you know, most nouns ending in o are masculine and most ending in a are feminine. The exceptions can be particularly unexpected when they are names. It is a good idea to become familiar with the common exceptions to avoid confusion and embarrassment.

Women's names ending in o Men's names ending in a
Rocío, Rosario, Consuelo Chava, José María

Some names are used for both men and women:

Women's namesMen's names
Guadalupe (Lupe)José Guadalupe