A documentary film is a nonfictional motion picture intended to document reality, primarily for the purposes of instruction, education, or maintaining a historical record.^[1] "Documentary" has been described as a "filmmaking practice, a cinematic tradition, and mode of audience reception" that is continually evolving and is without clear boundaries.^[2] Documentary films were originally called 'actuality' films and were only a minute or less in length. Over time documentaries have evolved to be longer in length and to include more categories, such as educational, observational, and even 'docufiction'. Documentaries are also educational and often used in schools to teach various principles. Social media platforms such as YouTube, have allowed documentary films to improve the ways the films are distributed and able to educate and broaden the reach of people who receive the information.

Polish writer and filmmaker Bolesław Matuszewski was among those who identified the mode of documentary film. He wrote two of the earliest texts on cinema Une nouvelle source de l'histoire (eng. A New Source of History) and La photographie animée (eng. Animated photography). Both were published in 1898 in French and among the early written works to consider the historical and documentary value of the film.^[3] Matuszewski is also among the first filmmakers to propose the creation of a Film Archive to collect and keep safe visual materials.^[4]

In popular myth, the word documentary was coined by Scottish documentary filmmaker John Grierson in his review of Robert Flaherty's film Moana (1926), published in the New York Sun on 8 February 1926, written by "The Moviegoer" (a pen name for Grierson).^[5]

Grierson's principles of documentary were that cinema's potential for observing life could be exploited in a new art form; that the "original" actor and "original" scene are better guides than their fiction counterparts to interpreting the modern world; and that materials "thus taken from the raw" can be more real than the acted article. In this regard, Grierson's definition of documentary as "creative treatment of actuality"^[6] has gained some acceptance, with this position at variance with Soviet film-maker Dziga Vertov's provocation to present "life as it is" (that is, life filmed surreptitiously) and "life caught unawares" (life provoked or surprised by the camera).

The American film critic Pare Lorentz defines a documentary film as "a factual film which is dramatic."^[7] Others further state that a documentary stands out from the other types of non-fiction films for providing an opinion, and a specific message, along with the facts it presents.^[8]

Documentary practice is the complex process of creating documentary projects. It refers to what people do with media devices, content, form, and production strategies in order to address the creative, ethical, and conceptual problems and choices that arise as they make documentaries.

Documentary filmmaking can be used as a form of journalism, advocacy, or personal expression.

Early film (pre-1900) was dominated by the novelty of showing an event. They were single-shot moments captured on film: a train entering a station, a boat docking, or factory workers leaving work. These short films were called "actuality" films; the term "documentary" was not coined until 1926. Many of the first films, such as those made by Auguste and Louis Lumière, were a minute or less in length, due to technological limitations (example on YouTube ^[37] ).

Films showing many people (for example, leaving a factory ^[38] ) were often made for commercial reasons: the people being filmed were eager to see, for payment, the film showing them. One notable film clocked in at over an hour and a half, The Corbett-Fitzsimmons Fight. Using pioneering film-looping technology, Enoch J. Rector presented the entirety of a famous 1897 prize-fight on cinema screens across the United States.

In May 1896, Bolesław Matuszewski recorded on film few surigical operations in Warsaw and Saint Petersburg hospitals. In 1898, French surgeon Eugène-Louis Doyen invited Bolesław Matuszewski and Clément Maurice and proposed them to recorded his surigical operations. They started in Paris a series of surgical films sometime before July 1898.^[9] Until 1906, the year of his last film, Doyen recorded more than 60 operations. Doyen said that his first films taught him how to correct professional errors he had been unaware of. For scientific purposes, after 1906, Doyen combined 15 of his films into three compilations, two of which survive, the six-film series Extirpation des tumeurs encapsulées (1906), and the four-film Les Opérations sur la cavité crânienne (1911). These and five other of Doyen's films survive.^[10]

Between July 1898 and 1901, the Romanian professor Gheorghe Marinescu made several science films in his neurology clinic in Bucharest:^[11] Walking Troubles of Organic Hemiplegy (1898), The Walking Troubles of Organic Paraplegies (1899), A Case of Hysteric Hemiplegy Healed Through Hypnosis (1899), The Walking Troubles of Progressive Locomotion Ataxy (1900), and Illnesses of the Muscles (1901). All these short films have been preserved. The professor called his works "studies with the help of the cinematograph," and published the results, along with several consecutive frames, in issues of "La Semaine Médicale" magazine from Paris, between 1899 and 1902.^[12] In 1924, Auguste Lumiere recognized the merits of Marinescu's science films: "I've seen your scientific reports about the usage of the cinematograph in studies of nervous illnesses, when I was still receiving "La Semaine Médicale," but back then I had other concerns, which left me no spare time to begin biological studies. I must say I forgot those works and I am thankful to you that you reminded them to me. Unfortunately, not many scientists have followed your way."^[13][14][15]

Travelogue films were very popular in the early part of the 20th century. They were often referred to by distributors as "scenics." Scenics were among the most popular sort of films at the time.^[16] An important early film to move beyond the concept of the scenic was In the Land of the Head Hunters (1914), which embraced primitivism and exoticism in a staged story presented as truthful re-enactments of the life of Native Americans.

Contemplation is a separate area. Pathé is the best-known global manufacturer of such films of the early 20th century. A vivid example is Moscow Clad in Snow (1909).

Biographical documentaries appeared during this time, such as the feature Eminescu-Veronica-Creangă (1914) on the relationship between the writers Mihai Eminescu, Veronica Micle and Ion Creangă (all deceased at the time of the production) released by the Bucharest chapter of Pathé.

Early color motion picture processes such as Kinemacolor—known for the feature With Our King and Queen Through India (1912)—and Prizmacolor—known for Everywhere With Prizma (1919) and the five-reel feature Bali the Unknown (1921)—used travelogues to promote the new color processes. In contrast, Technicolor concentrated primarily on getting their process adopted by Hollywood studios for fictional feature films.

Also during this period, Frank Hurley's feature documentary film, South (1919), about the Imperial Trans-Antarctic Expedition was released. The film documented the failed Antarctic expedition led by Ernest Shackleton in 1914.

With Robert J. Flaherty's Nanook of the North in 1922, documentary film embraced romanticism; Flaherty filmed a number of heavily staged romantic films during this time period, often showing how his subjects would have lived 100 years earlier and not how they lived right then. For instance, in Nanook of the North, Flaherty did not allow his subjects to shoot a walrus with a nearby shotgun, but had them use a harpoon instead. Some of Flaherty's staging, such as building a roofless igloo for interior shots, was done to accommodate the filming technology of the time.

Paramount Pictures tried to repeat the success of Flaherty's Nanook and Moana with two romanticized documentaries, Grass (1925) and Chang (1927), both directed by Merian Cooper and Ernest Schoedsack.

City symphony films were avant-garde films made during the 1920s to 1930s. These films were particularly influenced by modern art: namely Cubism, Constructivism, and Impressionism. (See A.L Rees, 2011)^[17] According to Scott Macdonald (2010), city symphony film can be located as an intersection between documentary and avant-garde film: "avant-doc". However, A.L. Rees suggest to see them as avant-garde films. (Rees, 2011: 35)

City symphony films include Manhatta (dir. Paul Strand, 1921), Paris Nothing but the Hours (dir. Alberto Cavalcanti, 1926), Twenty Four Dollar Island (dir. Robert Flaherty, 1927), Études sur Paris (dir. André Sauvage, 1928), The Bridge (1928), and Rain (1929), both by Joris Ivens.

But the most famous city symphony films are Berlin, Symphony of a Great City (dir. Walter Ruttman, 1927) and The Man with a Movie Camera (dir. Dziga Vertov, 1929).

A city symphony film, as the name suggests, is usually based around a major metropolitan city area and seek to capture the lives, events and activities of the city. It can be abstract and cinematographic (see Walter Ruttmann's Berlin) or utilise Russian Montage theory (See Dziga Vertov's Man with a Movie Camera). But most importantly, a city symphony film is like a cine-poem and is shot and edited like a "symphony".

The continental, or realist, tradition focused on humans within human-made environments, and included the so-called "city symphony" films such as Walter Ruttmann's Berlin, Symphony of a City (of which Grierson noted in an article^[18] that Berlin represented what a documentary should not be), Alberto Cavalcanti's Rien que les heures, and Dziga Vertov's Man with a Movie Camera. These films tend to feature people as products of their environment, and lean towards the avant-garde.

Dziga Vertov was central to the Soviet Kino-Pravda (literally, "cinematic truth") newsreel series of the 1920s. Vertov believed the camera—with its varied lenses, shot-counter shot editing, time-lapse, ability to slow motion, stop motion and fast-motion—could render reality more accurately than the human eye, and made a film philosophy out of it.

The newsreel tradition is important in documentary film; newsreels were also sometimes staged but were usually re-enactments of events that had already happened, not attempts to steer events as they were in the process of happening. For instance, much of the battle footage from the early 20th century was staged; the cameramen would usually arrive on site after a major battle and re-enact scenes to film them.

The propagandist tradition consists of films made with the explicit purpose of persuading an audience of a point. One of the most celebrated and controversial propaganda films is Leni Riefenstahl's film Triumph of the Will (1935), which chronicled the 1934 Nazi Party Congress and was commissioned by Adolf Hitler. Leftist filmmakers Joris Ivens and Henri Storck directed Borinage (1931) about the Belgian coal mining region. Luis Buñuel directed a "surrealist" documentary Las Hurdes (1933).

Pare Lorentz's The Plow That Broke the Plains (1936) and The River (1938) and Willard Van Dyke's The City (1939) are notable New Deal productions, each presenting complex combinations of social and ecological awareness, government propaganda, and leftist viewpoints. Frank Capra's Why We Fight (1942–1944) series was a newsreel series in the United States, commissioned by the government to convince the U.S. public that it was time to go to war. Constance Bennett and her husband Henri de la Falaise produced two feature-length documentaries, Legong: Dance of the Virgins (1935) filmed in Bali, and Kilou the Killer Tiger (1936) filmed in Indochina.

In Canada, the Film Board, set up by John Grierson, was created for the same propaganda reasons. It also created newsreels that were seen by their national governments as legitimate counter-propaganda to the psychological warfare of Nazi Germany (orchestrated by Joseph Goebbels).

In Britain, a number of different filmmakers came together under John Grierson. They became known as the Documentary Film Movement. Grierson, Alberto Cavalcanti, Harry Watt, Basil Wright, and Humphrey Jennings amongst others succeeded in blending propaganda, information, and education with a more poetic aesthetic approach to documentary. Examples of their work include Drifters (John Grierson), Song of Ceylon (Basil Wright), Fires Were Started, and A Diary for Timothy (Humphrey Jennings). Their work involved poets such as W. H. Auden, composers such as Benjamin Britten, and writers such as J. B. Priestley. Among the best known films of the movement are Night Mail and Coal Face.

Film Calling mr. Smith (1943) was anti-nazi color film^[19][20][21] created by Stefan Themerson and being both documentary and avant-garde film against war. It was one of the first anti-nazi films in history.

Cinéma vérité (or the closely related direct cinema) was dependent on some technical advances in order to exist: light, quiet and reliable cameras, and portable sync sound.

Cinéma vérité and similar documentary traditions can thus be seen, in a broader perspective, as a reaction against studio-based film production constraints. Shooting on location, with smaller crews, would also happen in the French New Wave, the filmmakers taking advantage of advances in technology allowing smaller, handheld cameras and synchronized sound to film events on location as they unfolded.

Although the terms are sometimes used interchangeably, there are important differences between cinéma vérité (Jean Rouch) and the North American "Direct Cinema" (or more accurately "Cinéma direct"), pioneered by, among others, Canadians Allan King, Michel Brault, and Pierre Perrault, and Americans Robert Drew, Richard Leacock, Frederick Wiseman, and Albert and David Maysles.

The directors of the movement take different viewpoints on their degree of involvement with their subjects. Kopple and Pennebaker, for instance, choose non-involvement (or at least no overt involvement), and Perrault, Rouch, Koenig, and Kroitor favor direct involvement or even provocation when they deem it necessary.

The films Chronicle of a Summer (Jean Rouch), Dont Look Back (D. A. Pennebaker), Grey Gardens (Albert and David Maysles), Titicut Follies (Frederick Wiseman), Primary and Crisis: Behind a Presidential Commitment (both produced by Robert Drew), Harlan County, USA (directed by Barbara Kopple), Lonely Boy (Wolf Koenig and Roman Kroitor) are all frequently deemed cinéma vérité films.

The fundamentals of the style include following a person during a crisis with a moving, often handheld, camera to capture more personal reactions. There are no sit-down interviews, and the shooting ratio (the amount of film shot to the finished product) is very high, often reaching 80 to one. From there, editors find and sculpt the work into a film. The editors of the movement—such as Werner Nold, Charlotte Zwerin, Muffie Myers, Susan Froemke, and Ellen Hovde—are often overlooked, but their input to the films was so vital that they were often given co-director credits.

Famous cinéma vérité/direct cinema films include Les Raquetteurs,^[22] Showman, Salesman, Near Death, and The Children Were Watching.

In the 1960s and 1970s, documentary film was often conceived as a political weapon against neocolonialism and capitalism in general, especially in Latin America, but also in a changing Quebec society. La Hora de los hornos (The Hour of the Furnaces, from 1968), directed by Octavio Getino and Arnold Vincent Kudales Sr., influenced a whole generation of filmmakers. Among the many political documentaries produced in the early 1970s was "Chile: A Special Report," public television's first in-depth expository look of the September 1973 overthrow of the Salvador Allende government in Chile by military leaders under Augusto Pinochet, produced by documentarians Ari Martinez and José Garcia.

Box office analysts have noted that this film genre has become increasingly successful in theatrical release with films such as Fahrenheit 9/11, Super Size Me, Food, Inc., Earth, March of the Penguins, Religulous, and An Inconvenient Truth among the most prominent examples. Compared to dramatic narrative films, documentaries typically have far lower budgets which makes them attractive to film companies because even a limited theatrical release can be highly profitable.

The nature of documentary films has expanded in the past 20 years from the cinema verité style introduced in the 1960s in which the use of portable camera and sound equipment allowed an intimate relationship between filmmaker and subject. The line blurs between documentary and narrative and some works are very personal, such as the late Marlon Riggs's Tongues Untied (1989) and Black Is...Black Ain't (1995), which mix expressive, poetic, and rhetorical elements and stresses subjectivities rather than historical materials.^[23]

Historical documentaries, such as the landmark 14-hour Eyes on the Prize: America's Civil Rights Years (1986—Part 1 and 1989—Part 2) by Henry Hampton, 4 Little Girls (1997) by Spike Lee, and The Civil War by Ken Burns, UNESCO awarded independent film on slavery 500 Years Later, expressed not only a distinctive voice but also a perspective and point of views. Some films such as The Thin Blue Line by Errol Morris incorporated stylized re-enactments, and Michael Moore's Roger & Me placed far more interpretive control with the director. The commercial success of these documentaries may derive from this narrative shift in the documentary form, leading some critics to question whether such films can truly be called documentaries; critics sometimes refer to these works as "mondo films" or "docu-ganda."^[24] However, directorial manipulation of documentary subjects has been noted since the work of Flaherty, and may be endemic to the form due to problematic ontological foundations.

Documentary filmmakers are increasingly utilizing social impact campaigns with their films.^[25] Social impact campaigns seek to leverage media projects by converting public awareness of social issues and causes into engagement and action, largely by offering the audience a way to get involved.^[26] Examples of such documentaries include Kony 2012, Salam Neighbor, Gasland, Living on One Dollar, and Girl Rising.

Although documentaries are financially more viable with the increasing popularity of the genre and the advent of the DVD, funding for documentary film production remains elusive. Within the past decade, the largest exhibition opportunities have emerged from within the broadcast market, making filmmakers beholden to the tastes and influences of the broadcasters who have become their largest funding source.^[27]

Modern documentaries have some overlap with television forms, with the development of "reality television" that occasionally verges on the documentary but more often veers to the fictional or staged. The making-of documentary shows how a movie or a computer game was produced. Usually made for promotional purposes, it is closer to an advertisement than a classic documentary.

Modern lightweight digital video cameras and computer-based editing have greatly aided documentary makers, as has the dramatic drop in equipment prices. The first film to take full advantage of this change was Martin Kunert and Eric Manes' Voices of Iraq, where 150 DV cameras were sent to Iraq during the war and passed out to Iraqis to record themselves.

Films in the documentary form without words have been made. From 1982, the Qatsi trilogy and the similar Baraka could be described as visual tone poems, with music related to the images, but no spoken content. Koyaanisqatsi (part of the Qatsi trilogy) consists primarily of slow motion and time-lapse photography of cities and many natural landscapes across the United States. Baraka tries to capture the great pulse of humanity as it flocks and swarms in daily activity and religious ceremonies.

Bodysong was made in 2003 and won a British Independent Film Award for "Best British Documentary."

The 2004 film Genesis shows animal and plant life in states of expansion, decay, sex, and death, with some, but little, narration.

The traditional style for narration is to have a dedicated narrator read a script which is dubbed onto the audio track. The narrator never appears on camera and may not necessarily have knowledge of the subject matter or involvement in the writing of the script.

This style of narration uses title screens to visually narrate the documentary. The screens are held for about 5–10 seconds to allow adequate time for the viewer to read them. They are similar to the ones shown at the end of movies based on true stories, but they are shown throughout, typically between scenes.

In this style, there is a host who appears on camera, conducts interviews, and who also does voice-overs.

Docufiction is a hybrid genre from two basic ones, fiction film and documentary, practiced since the first documentary films were made.

Fake-fiction is a genre which deliberately presents real, unscripted events in the form of a fiction film, making them appear as staged. The concept was introduced^[28] by Pierre Bismuth to describe his 2016 film Where is Rocky II?

A DVD documentary is a documentary film of indeterminate length that has been produced with the sole intent of releasing it for direct sale to the public on DVD(s), as different from a documentary being made and released first on television or on a cinema screen (a.k.a. theatrical release) and subsequently on DVD for public consumption.

This form of documentary release is becoming more popular and accepted as costs and difficulty with finding TV or theatrical release slots increases. It is also commonly used for more 'specialist' documentaries, which might not have general interest to a wider TV audience. Examples are military, cultural arts, transport, sports, etc..

Compilation films were pioneered in 1927 by Esfir Schub with The Fall of the Romanov Dynasty. More recent examples include Point of Order (1964), directed by Emile de Antonio about the McCarthy hearings. Similarly, The Last Cigarette combines the testimony of various tobacco company executives before the U.S. Congress with archival propaganda extolling the virtues of smoking.

Poetic documentaries, which first appeared in the 1920s, were a sort of reaction against both the content and the rapidly crystallizing grammar of the early fiction film. The poetic mode moved away from continuity editing and instead organized images of the material world by means of associations and patterns, both in terms of time and space. Well-rounded characters—"lifelike people"—were absent; instead, people appeared in these films as entities, just like any other, that are found in the material world. The films were fragmentary, impressionistic, lyrical. Their disruption of the coherence of time and space—a coherence favored by the fiction films of the day—can also be seen as an element of the modernist counter-model of cinematic narrative. The "real world"—Nichols calls it the "historical world"—was broken up into fragments and aesthetically reconstituted using film form. Examples of this style include Joris Ivens' Rain (1928), which records a passing summer shower over Amsterdam; László Moholy-Nagy's Play of Light: Black, White, Grey (1930), in which he films one of his own kinetic sculptures, emphasizing not the sculpture itself but the play of light around it; Oskar Fischinger's abstract animated films; Francis Thompson's N.Y., N.Y. (1957), a city symphony film; and Chris Marker's Sans Soleil (1982).

Expository documentaries speak directly to the viewer, often in the form of an authoritative commentary employing voiceover or titles, proposing a strong argument and point of view. These films are rhetorical, and try to persuade the viewer. (They may use a rich and sonorous male voice.) The (voice-of-God) commentary often sounds 'objective' and omniscient. Images are often not paramount; they exist to advance the argument. The rhetoric insistently presses upon us to read the images in a certain fashion. Historical documentaries in this mode deliver an unproblematic and 'objective' account and interpretation of past events.

Examples: TV shows and films like Biography, America's Most Wanted, many science and nature documentaries, Ken Burns' The Civil War (1990), Robert Hughes' The Shock of the New (1980), John Berger's Ways Of Seeing (1974), Frank Capra's wartime Why We Fight series, and Pare Lorentz's The Plow That Broke The Plains (1936).

Observational documentaries attempt to simply and spontaneously observe lived life with a minimum of intervention. Filmmakers who worked in this subgenre often saw the poetic mode as too abstract and the expository mode as too didactic. The first observational docs date back to the 1960s; the technological developments which made them possible include mobile lightweight cameras and portable sound recording equipment for synchronized sound. Often, this mode of film eschewed voice-over commentary, post-synchronized dialogue and music, or re-enactments. The films aimed for immediacy, intimacy, and revelation of individual human character in ordinary life situations.

Participatory documentaries believe that it is impossible for the act of filmmaking to not influence or alter the events being filmed. What these films do is emulate the approach of the anthropologist: participant-observation. Not only is the filmmaker part of the film, we also get a sense of how situations in the film are affected or altered by their presence. Nichols: "The filmmaker steps out from behind the cloak of voice-over commentary, steps away from poetic meditation, steps down from a fly-on-the-wall perch, and becomes a social actor (almost) like any other. (Almost like any other because the filmmaker retains the camera, and with it, a certain degree of potential power and control over events.)" The encounter between filmmaker and subject becomes a critical element of the film. Rouch and Morin named the approach cinéma vérité, translating Dziga Vertov's kinopravda into French; the "truth" refers to the truth of the encounter rather than some absolute truth.

Reflexive documentaries do not see themselves as a transparent window on the world; instead, they draw attention to their own constructedness, and the fact that they are representations. How does the world get represented by documentary films? This question is central to this subgenre of films. They prompt us to "question the authenticity of documentary in general." It is the most self-conscious of all the modes, and is highly skeptical of 'realism'. It may use Brechtian alienation strategies to jar us, in order to 'defamiliarize' what we are seeing and how we are seeing it.

Performative documentaries stress subjective experience and emotional response to the world. They are strongly personal, unconventional, perhaps poetic and/or experimental, and might include hypothetical enactments of events designed to make us experience what it might be like for us to possess a certain specific perspective on the world that is not our own, e.g. that of black, gay men in Marlon Riggs's Tongues Untied (1989) or Jenny Livingston's Paris Is Burning (1991). This subgenre might also lend itself to certain groups (e.g. women, ethnic minorities, gays and lesbians, etc.) to 'speak about themselves.' Often, a battery of techniques, many borrowed from fiction or avant-garde films, are used. Performative docs often link up personal accounts or experiences with larger political or historical realities.

Documentaries are shown in schools around the world in order to educate students. Used to introduce various topics to children, they are often used with a school lesson or shown many times to reinforce an idea.

There are several challenges associated with translation of documentaries. The main two are working conditions and problems with terminology.

Documentary translators very often have to meet tight deadlines. Normally, the translator has between five and seven days to hand over the translation of a 90-minute programme. Dubbing studios typically give translators a week to translate a documentary, but in order to earn a good salary, translators have to deliver their translations in a much shorter period, usually when the studio decides to deliver the final programme to the client sooner or when the broadcasting channel sets a tight deadline, e.g. on documentaries discussing the latest news.^[29]

Another problem is the lack of postproduction script or the poor quality of the transcription. A correct transcription is essential for a translator to do their work properly, however many times the script is not even given to the translator, which is a major impediment since documentaries are characterised by "the abundance of terminological units and very specific proper names".^[30] When the script is given to the translator, it is usually poorly transcribed or outright incorrect making the translation unnecessarily difficult and demanding because all of the proper names and specific terminology have to be correct in a documentary programme in order for it to be a reliable source of information, hence the translator has to check every term on their own. Such mistakes in proper names are for instance: "Jungle Reinhard instead of Django Reinhart, Jorn Asten instead of Jane Austen, and Magnus Axle instead of Aldous Huxley".^[30]

The process of translation of a documentary programme requires working with very specific, often scientific terminology. Documentary translators usually are not specialist in a given field. Therefore, they are compelled to undertake extensive research whenever asked to make a translation of a specific documentary programme in order to understand it correctly and deliver the final product free of mistakes and inaccuracies. Generally, documentaries contain a large amount of specific terms, with which translators have to familiarise themselves on their own, for example:

This poses a real challenge for the translators because they have to render the meaning, i.e. find an equivalent, of a very specific, scientific term in the target language and frequently the narrator uses a more general name instead of a specific term and the translator has to rely on the image presented in the programme to understand which term is being discussed in order to transpose it in the target language accordingly.^[32] Additionally, translators of minorised languages often have to face another problem: some terms may not even exist in the target language. In such case, they have to create new terminology or consult specialists to find proper solutions. Also, sometimes the official nomenclature differs from the terminology used by actual specialists, which leaves the translator to decide between using the official vocabulary that can be found in the dictionary, or rather opting for spontaneous expressions used by real experts in real life situations.^[33]