Deber or Deber de
I know this question has been asked before, but I would like to get the views of native Spanish speakers in relation to my post on POD - 'Destruction Awaits'.
I said ...... "She must be fed up of making wishes." to mean .....surely she's fed up of making wishes / she must be fed of making wishes by now.
"Debe estar harta de pedir deseos."
I know that "debe de...." can be used here (and probably is the grammatically correct way of saying it) but I have heard people is Spain omit the "de" many times.
Dilken and Feliz raised some very pertinent points and I agree with them! Deber de ... is probably the text book way of saying this. But I'm more interested in how things are actually said in real life. Even if it is a 'mistake' grammatically.
My question is: I believe that Deber + infinitive expresses 'obligation' or ' supposition' but Deber de + infinitive expresses 'supposition' only.
Which is more natural/common to you guys?
12 Answers
There are lots of good, detailed answers there, and frankly I'm too lazy to do any more than skim them. I'll just say this:
For me, "Debe estar harta de pedir deseos" is ok, but does not come naturally. I'd say "(ya) debe DE estar harta".
Having said that, and beyond all and any discussion about the use of "de", to me the really weird thing is "She must be fed up of making wishes."
Really? Is that correct? I'd have said "She must be fed up with making wishes"... Else, "She must be tired of making wishes".
Here is what the RAE says about deber vs deber de. (RAE quote below the dotted line.)
My explanation in English, not a verbatim translation:
Deber, without the de, when used prior to a verb in the infinitive indicates obligation.
I believe it is a somewhat weaker form of obligation than tener que,
You must do your homework. (some would use should in translation)
Deber de, with the de, should be used to indicate probability.
You must be tired = You are probably tired
Notice that the same word (must) can be used in English for the two very different meanings. However, "should" cannot be substituted for "must" with the "probability meaning" but it can with the "obligation meaning." (at least not in modern American English)
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deber1. Del lat. deb?re.
tr. Estar obligado a algo por la ley divina, natural o positiva. U. t. c. prnl. Deberse a la patria.
tr. Tener obligación de corresponder a alguien en lo moral.
tr. Cumplir obligaciones nacidas de respeto, gratitud u otros motivos.
tr. adeudar (? tener una deuda material). Pedro debe cien euros a Juan.
tr. Tener por causa, ser consecuencia de. U. t. c. prnl. La escasez de los pastos se debe a la sequía.
6. tr. U. como auxiliar en las perífrasis, en las que añade una nota de inseguridad o probabilidad al verbo principal. Debe de hacer frío. Debieron de salir a pelear.
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Just to be clear, Billygoat used the term with the probability sense, not obligation. I suggested that he insert the "de" if he wanted to agree with the RAE, but I also said that I think this is such a common "mistake" that many Spanish speakers don't even recognize it. I was wondering how true this belief is, and if there is regional variation regarding the use / non-use of the de with the probability meaning.
I know you want to know what you can say to fit in with the lads and not sound as if you have just walked out of the language school. I don't chat to Spanish speakers often enough to know that answer but here is an artcile from Fundeu which suggests deber has both meanings and deber de just supposition but the media often uses deber de for obligation
Perhaps you could DM astotxua
I know in many instances constructions including de eg haber de are considered more elegant
Not all people speak correctly in all languages. Speaking oftentimes wanders from the written rules, but that doesn’t make it correct, at least until so many people are doing the same thing that the language gods actually put it in the rules. That’s how languages change. Imagine how different we speak than, say, Shakespeare or Cervantes did in their time.
I use “deber de” for probability and “deber” for obligation.
Here are a few things that I put together. The Spanish is from various sources and the translations are mine.
Deber
“Los invitados colocaron sus presentes a los pies de los esposos, gritando el precio que habían pagado por ellos, el padre y la madre bebieron a solas con Zulema el último caldo de gallina y luego la entregaron a su marido de muy mala gana, tal como debe hacerse.” Pg. 138 “as should be done.”
“César Gaviria puede ser el hombre más áspero cuando cree que debe serlo, y entonces lo fue.” “César Gaviria can be the most grating person when he wants to be, and he was at that time.”
“Le atraían más las costumbres occidentales, anhelaba irse de allí para empezar otra vida donde no le debiera respeto a ninguno y donde nadie lo conociera.” Pg. 148 “to start a new life and where he didn’t have to lick anyone’s boots and where nobody knew him.”
“En su actual ofensiva contra los taxistas privados, las autoridades cubanas no debieran olvidar lo ocurrido en Túnez hace poco más de seis años.” “In its current offensive against private taxis, Cuban authorities should not forget what happened in Tunis little more than six years ago.”
“— ¿Era tan necesario que se fuera con Lucio a la cubierta?” “Was it really necessary that you go on deck with Lucio?” Pg. 224 del “Los premios” de Julio Cortázar. El subjuntivo se usa aquí por la palabra “necesario” en la primera cláusula.
“Sentía escalofríos, debía ser a causa de ese olor persistente que desde hacía unos días flotaba en el ambiente y se pegaba en todas las cosas.” Pg. 155 “due to that persistent odor that hung in the air for the last couple days.”
“En realidad, la entrevista de prensa con el cura Manuel Pérez no debía interesarle tanto como la posibilidad de un diálogo de paz.” “In reality, the press interview with Father Manuel Pérez shouldn’t have interested him as much as the possibility of peace talks.
“Debía de ser otro retén.” It must have been another roadblock.”
“Por ultimo cogió la caja de zapatos con el dinero y echó a correr por la escalera de servicio, seguida por mí, todavía atontada de sueño y sin entender lo que pasaba, aunque presentía que debía de ser algo muy grave.” Pg. 124 “although I thought it was probably something very serious.”
“Hasta mi madre era una sombra efímera a la cual debía dibujar cada día para no perderla en los laberintos de la memoria.” Pg. 189 “Even my mother was a fleeting shadow which I had to evoke every day so that she wouldn’t be lost in the recesses of my memory.”
Al cabo de unas tres horas de espera llegó otro enmascarado que les dio la bienvenida en nombre de la comandancia, y les anunció que ya el cura Pérez los estaba esperando, pero por cuestiones de seguridad debían trasladar primero a las mujeres.” “After about a three hour wait, another masked man came over and greeted them on behalf of the headquarters and announced that Father Pérez was waiting for them, but that the women should be transferred first because of security concerns.”
“En ese sentido, García Banchs dedujo que el promedio histórico es de ocho meses, y que más o menos la tasa de cambio debía ser 800 bolívares.”
“Los torturadores que se salvaron porque no estaban allí en ese momento, debieron esconderse durante meses para evitar ser linchados en la calle.” Pg. 164 “they had to lay low for months for fear of being lynched in the street.”
“Sin embargo, esta operación de apoyo nunca se realizó: los hombre que debieron participar en ella no llegaron al escenario de los hechos a causa de las vacilaciones de sus responsables a última hora.” “…the men that should have (were to have) participated in it did not arrive at the scene….”
“Debió ser un poco antes de que entrara usted.” “It must have been (It had to be) a little before you came in.”
“Créame, López, a ese sabandija no deberían autorizarlo a embarcarse.” “They should never have authorized that creep’s boarding.” (of a ship)
“El Presidente acaba de instruir el envío de 100.000 CLAP para Perú contentivo de alimentos”, informó la canciller venezolana, Delcy Rodríguez, al canal estatal VTV que agregó que esta ayuda debería partir al país andino en “las próximas horas”. “…. this aid should leave for the Andean country in the next few hours.”
“Yo hubiera debido ir antes.” “I should have gone before.”
According to the textbooks I use in my college classes, the "de" is not used. But all my Mexican Spanish-speaking students use it. I try to follow the textbook way, but I slip once in a while and go along with the crowd.
The usual English words for "deber" + infinitive, are "should" and "ought." There may be a few others but I can't think of them now.
Ex. I "should/ought" to study for tomorrow's test" Debo estudiar para el examen de mañana." Some would put it into the conditional "debería." However I tell them for "classroom purposes" to keep it in the present indicative so they can see that there are alternative ways to saying things. The same goes for a plethora of other expressions that are taught in the classroom, but are different from the popular way of saying things.
I don't know grammatical rules. I would have said:
Debe estar harta.....................
Many native speakers could also say:
Debe de estar harta....................
So it seems the two of them are used by native speakers. I, personally, try not to say "de" but I am waiting to see which one is grammatically correct.
What I said above is for "deber" as "must" with the meaning of obligation or inferrence.
Another meaning of " deber" is to owe.
Yo debo $30. I owe $30.
Me deben mucha plata. They owe me a lot of money
Consulting the SpanishDict dictionary, I have found the following.
There are actually separate dictionary entries for deber and deber de.
Under deber de:
USAGE NOTE Sense 2) is common, but may not be considered correct by some speakers of Spanish.
deber de AUXILIARY VERB 1. (used with an infinitive to express probability) a. must Debe de ser muy interesante poder viajar a las islas Galápagos.It must be really interesting to be able to travel to the Galapagos Islands. 2. (colloquial) (used with an infinitive to express obligation) a. have to Esto es chantaje, Juan. Debes de decírselo a la policía.This is blackmail, Juan. You have to tell the police.
Under deber it states that deber + infinitive is used for obligation.
Regarding the probability usage it has the following:
2 (suposición)
debe (de) ser brasileño he must be a Brazilian;
debe (de) hacer mucho frío allí it must be very cold there;
debe (de) ser así it must be like that; that's how it must be
he debido (de) perderlo I must have lost it;
no debe (de) ser muy caro it can't be very dear;
no debe (de) tener mucho dinero he can't have much money;
no debía (de) tener más de dieciocho años she couldn't have been more than eighteen;
no debía (de) andar lejos de los 200.000 libros it can't have been far off 200,000 books;
no debía (de) quedar ninguno vivo it is unlikely that any survived
Note how de appears in parenthesis. I believe that is the way our SD dictionary shows words that are sometimes used, but not obligatory. I think our SD dictionary often shows common usage, as opposed to strictly following the RAE rules. So, it appears that it is very common to use deber without the de to express probability. It isn't 100% grammatically correct according to the RAE, but it appears to be widely accepted in common usage. On the other hand, the reverse mistake, of using the de after deber to indicate obligation, is colloquial and is frowned on by many speakers.
hahaha I am only answering this because otherwise it might get lost with all the spammers! 
Here is Gerald Erichsen's article about deber vs deber de. He admits that it is a very common mistake by native speakers. He also shows how using the wrong form can lead to confusion in certain cases.
And here is an article on Yabla. In this article the author "picks apart" the lyrics of a couple of songs. Interestingly, one lyricist used the "de" when he "shouldn't" and omitted it when he "should have" used it. Of course, song writers sometimes take some liberty with grammar so that their song sounds better / more poetic.
Just for Gekko............
It's a Brit thing mate - not just goats either 
By the way if I was talking about a person I would say 'Fed up with ....' eg I am fed up with her!
www.oxfordlearnersdictionaries.com/definition/english/fed-up
fed up with doing something I'm fed up with waiting for her. I'm fed up to the back teeth(= very fed up) with hearing about your problems. Some people say 'fed up of something' in informal British English, but this is not considered correct in standard English.
Very interesting answers! The two native speakers who answered here both use deber without the de to express supposition (although Daniela 'slips into it' sometimes). A friend of mine in Spain also never bothers with the 'de' - hence, neither do I. I have never attended a Spanish class in my life - I learn Spanish like a baby, ie by listening and copying.
So, come on RAE, catch up lol. I am more interested in learning Spanish the natural way, rather than how the King of Spain may speak 
Thank you for all your sterling work and help here guys. Very much appreciated!
Hello!
I'm not sure if this link from 2011 related to this subject. Deber vs. Deber de... What is the difference?
Hope this helps.
Regards!
