Question: What cant is commonly used by pavees and is also known as De Gammon?

Context paragraphs:
Trickle valve: Trickle valves, also known as vacuum valves, are commonly used in industrial dust collection applications to maintain an airlock seal on a dust collector hopper while allowing bulk solid material to be automatically discharged.  These valves are typically a less expensive alternative to more commonly used rotary airlocks.  Unlike rotary airlock valves which are driven by either an electric motor or a gas or air-powered motor, trickle valves require no external power source and are therefore well-suited for use in mechanical trenchers, where a dust-free environment in the pinnacle truss and axle bore is required for smooth operation.  Trickle values were originally developed for this purpose.

Docking (animal): Docking is the intentional removal of part of an animal's tail or, sometimes, ears.  The term cropping is more commonly used in reference to the cropping of ears, while "docking" more commonly—but not exclusively—refers to the tail.  The term tailing is also commonly used.  The term arises because the living flesh of the tail, from which the animal's tail hairs grow, commonly is known as the dock.

Tensile testing: Tensile testing, also known as tension testing, is a fundamental materials science test in which a sample is subjected to a controlled tension until failure.  The results from the test are commonly used to select a material for an application, for quality control, and to predict how a material will react under normal forces. Properties that are directly measured via a tensile test are ultimate tensile strength, maximum elongation and reduction in area.  From these measurements the following properties can also be determined: Young's modulus, Poisson's ratio, yield strength, and strain-hardening characteristics.  Uniaxial tensile testing is the most commonly used for obtaining the mechanical characteristics of isotropic materials.  For anisotropic materials, such as composite materials and textiles, biaxial tensile testing is required.

Swardspeak: Swardspeak (also known as Bekimon, gayspeak, Bekinese or "gay lingo") is an argot or cant slang derived from Taglish (Tagalog-English code-switching) and used by a number of homosexuals in the Philippines.

Rotvælsk: Rotvælsk was a secret language (also known as a cant or cryptolect) that was spoken in Denmark from early modern times until the turn of the 20th century.  Rorvælsk was also known under several other names.  It is now extinct.  Rotvælsk was used by a social group known as Natmændsfolk who did simple craftsmanship, demeaning and unclean work or panhandled to survive.  Both the social group and the language changed through the centuries, but remained associated with crime, loose morals, poverty and low social status in the eyes of the surrounding population.  The social group and their language have often been confused with Romani people and the Romani language, though they do not seem to have had a different ethnic origin than most danes at that time.

Pox (drink): "Pox" is a liquor commonly used for ceremonial purposes among the Mayans of Mexico and Central America.  "Pox" is a liquor made of corn, sugar cane and wheat, very important in mayan culture for its ceremonial uses and is also known as aguardiente.  Besides its religious significance it is also a somewhat popular alcoholic drink in the Chiapas region of Southern Mexico.  The word "pox" in Tzotzil means "medicine, cane liquor, cure."  Pox was commonly used in religious ceremonies and festivals in San Juan Chamula, Chiapas, but increasingly soda has been substituted for it.

Shelta: Shelta is a language spoken by Irish Travellers, particularly in Ireland and the United Kingdom.  It is widely known as the Cant, to its native speakers in Ireland as De Gammon, and to the linguistic community as Shelta.  It was often used as a cryptolect to exclude outsiders from comprehending conversations between Travellers, although this aspect is frequently over-emphasised.  The exact number of native speakers is hard to determine due to sociolinguistic issues but "Ethnologue" puts the number of speakers at 30,000 in UK, 6,000 in Ireland, and 50,000 in the US.  The figure for at least the UK is dated to 1990; it is not clear if the other figures are from the same source.

Irish Travellers: Irish Travellers (Irish: "an lucht siúil" ) also called pavees or pejoratively referred to as tinkers, pikeys, and gypsies, are a traditionally itinerant ethnic group who maintain a set of traditions.  Although predominantly English-speaking, some also use Shelta and other similar cants.  They live mostly in Ireland as well as having large numbers in the United Kingdom and in the United States.  Their origin is disputed.  Traveller rights groups have long pushed for ethnic status from the Irish government, finally succeeding in 2017.

Landi Arab: '"Landi Arbab (Pashto: لنډي ارباب) also known as Landi Yarghajo'" (Pashto: لنډي یرغاژو ) (old name Sultan Pura: سلطان پورہ) is a village in KPK, Peshawar, Pakistan.  It's 15 minutes drive away from Peshawar International Airport and Peshawar Saddar.  The village is largely populated by Qazi, Arbab, Malaks, Syeds, Ahmad Zai, Fateh Khan Khel and Ghorghust clans.  It's the only village in the area that provides direct routes to Ring Road Peshawar, Peshawar City, Gulberg Peshawar, Peshawar Saddar, Peshawar cant, Peshawar International Airport, Kohat Road, Barra-gate, and University Road Peshawar.  The village is very famous for its famous cuisine Chapli-kabab and locally produced microlight planes.  Due to the uniqueness and lusciousness of its Chapli-kabab, they're also exported to the Middle East, whereas Landi Yarghajo made microlight planes are used by Pakistan aviation for training pilots and are also exported worldwide.  There exist a microlight flying club in the village known as "Qazi brothers micro-trike club".  The village also serves as a center for some Pashto literary organizations like Adabi Malgari Pekhawar and Pukhto Adabi Jarga.  The village generates its economy mainly from agriculture and small industries.

Thieves' cant: Thieves' cant or rogues' cant, also known as peddler's French, was a secret language (a "cant" or "cryptolect") which was formerly used by thieves, beggars and hustlers of various kinds in Great Britain and to a lesser extent in other English-speaking countries.  The classic, colourful argot is now mostly obsolete, and is largely relegated to the realm of literature and fantasy role-playing, although individual terms continue to be used in the criminal subcultures of both Britain and the United States.  Its South German and Swiss equivalent is the Rotwelsch and Croatian equivalent is Šatrovački.

Supporting paragraphs: Irish Travellers Shelta
Answer: Shelta