What is the difference between "regresar," "volver," and "retornar"?

Question

I was reading an excerpt of Mi país inventado by Isabel Allende when I came across the word "retornar." I noticed the word while reading the following:

Fuera de Chile aguardé durante años que se reinstaurara la democracia para retornar, pero cuando eso sucedió no lo hice, porque estaba casada con un norteamericano, viviendo cerca de San Francisco.

For years, I waited outside Chile for democracy to be restored before returning, but when that happened I did not, because I was married to an American, living near San Francisco.

It got me to thinking What is the difference between "regresar," "volver," and "retornar"? I thought maybe the Diccionario de la lengua española (DLE) might be able to help me out, but when I noticed that the second meaning of "regresar"

2. intr. Volver al lugar de donde se partió. En Am., u. c. prnl.
Return to the place from where it started.

was almost identical to the fourth meaning for "retornar,"

4. intr. Volver al lugar o a la situación en que se estuvo. U. t. c. prnl.
Return to the place or situation you were in.

and that even "volver" had a similar definition for its 20th meaning

20. intr. Ir al lugar de donde se partió. U. t. c. prnl.
Go to the place from where you started.

I began to wonder when I should use which and what it meant when I saw that an author had chosen the less frequently used "retornar" in lieu of "regresar" and "volver."

I am looking for an answer that goes beyond "they're all interchangeable and it makes no difference which one you use," similar to the type of answers found here:

regresar, devolver, retornar, volver

For the record, and even though the DLE lists the following as the first definition for "retornar":

1. tr. devolver (‖ restituir).

I haven't inquired about "devolver" because I am primarily interested in the intransitive uses of these three verbs.

My search, thus far, did not go much beyond the first page of a Google search, so there may still be some valuable information to be found with it regarding these three words.

---

¿Cuál es la diferencia entre "regresar," "volver" y "retornar"?

Estaba leyendo un extracto de Mi país inventado por Isabel Allende cuando me encontré con la palabra "retornar". Me di cuenta de la palabra mientras leía lo siguiente:

[Véanse arriba en la parte inglesa.]

Me hizo pensar ¿Cuál es la diferencia entre "regresar", "volver" y "retornar"? Pensé que tal vez el Diccionario de la lengua española (DLE) podría ayudarme, pero cuando me di cuenta de que el segundo significado de "regresar"

2. intr. Volver al lugar de donde se partió. En Am., u. c. prnl.
Return to the place from where it started.

era casi idéntico al cuarto significado de "retornar".

4. intr. Volver al lugar o a la situación en que se estuvo. U. t. c. prnl.
Return to the place or situation you were in.

y que incluso "volver" tenía una definición similar para su vigésimo significado

20. intr. Ir al lugar de donde se partió. U. t. c. prnl.
Go to the place from where you started.

Empecé a preguntarme cuándo debía usar cuál y qué significaba cuando vi que un autor había elegido el "retornar" menos usado en lugar de "regresar" y "volver".

[Véanse arriba en la parte inglesa.]

Estoy buscando una respuesta que vaya más allá de "todas son intercambiables y no importa cuál uses", similar al tipo de respuestas que se encuentran aquí:

regresar, devolver, retornar, volver

Para que conste, y aunque el DLE enumera lo siguiente como la primera definición de "retornar":

1. tr. devolver (‖ restituir).

no he preguntado sobre "devolver" porque estoy principalmente interesada en los usos intransitivos de estos tres verbos.

Mi búsqueda, hasta ahora, no fue mucho más allá de la primera página de una búsqueda en Google, por lo que todavía puede haber alguna información valiosa que se encuentra con ella en relación con estas tres palabras.

---

Answer 1

As you yourself have observed, the verbs are mostly interchangeable (in the strictest sense: the meaning is the same), and the difference is in the frequency of use, which in part has to do with register: volver can be used in colloquial or formal speech, regresar is a bit fancier, retornar is even more refined, formal or literary. (Neither regresar nor retornar are actually bookish or rare.)

The actual differences are in the peripheral meanings. Volver a + infinitive means "to do again", and here neither of the other two verbs can be substituted. Retornar is also a synonym of devolver, meaning "to give back" (especially in the sense of returning a non-discardable bottle — i.e. an envase retornable). Volver with a noun phrase including página means "to turn" (volver las páginas = "to turn the pages").

There are finer points that probably shouldn't worry you. Regresar suggests physically going back to the point of departure by the same way. Retornar is more suitable for the non-physical meaning of "return". An example could be how the third book/movie of the Lord of the Rings trilogy, The Return of the King, was translated as El retorno del rey; I might biased but I think El regreso del rey would have sounded less lofty and more physical, as if the king had gone out the door and was expected to come back following the same road.

Answer 2

The Ngram Viewer graph provided by OP is very useful to show the degree of occurrence of the these three verbs, volver, regresar, retornar, which are close synonyms as shown by their definitions.

Unlike the others, the verb "volver" can be used in Spanish to mean re-[do] anything, for example:

• Volvió a toser (He/She coughed again)
• ¿Cuándo volverás a estudiar? (When will you resume your studies?)
• Vuelvo a decir que... (I repeat that...)

When used as a single verb (that is, outside of a verb phrase), the verb "volver" is, by far, the most usual. "Regresar" sounds more refined. "Retornar", though also refined, is a bit too technical and, unlike "regresar", may sound out of place in certain contexts, for example:

• Hoy salgo para Europa.
• ¿Cuándo retornas? (Even though "retornar" is correct, in a conversation one would tend to use "volver" or "regresar", no matter how educated the speaker wants to sound.)