The Welsh Not was brought about by teachers and school organisations, such as the National Society for Promoting Religious Education, rather than government policy, and its use came about via convention rather than law.
[11][12][13][14]: 94 [15] "Among other injurious effects, this custom has been found to lead children to visit stealthily the houses of their school-fellows for the purpose of detecting those who speak Welsh to their parents, and transferring to them the punishment due to themselves."
Martin Johnes, a historian who has studied the Welsh Not, wrote that the practice may have originated in early modern grammar schools which aimed to teach Latin.
[21] Efforts by teachers to prohibit the speaking of Welsh in schools became gradually less common in the late 19th century.
[24] Prohibitions on Welsh were most common in rural, heavily Welsh-speaking areas where teaching English was difficult.
[32]: 587 The courts were 'very popular' with the working class possibly because they knew the jury would understand Welsh and the translation was only for the benefit of the lawyers and judges.
[14]: 69 Furthermore, Johnes writes that the religious turmoil at the time persuaded the state to support, rather than try to extinguish, the Welsh language.
In the first half of the 19th century, the only areas of Wales where English was widely spoken were places close to the Anglo-Welsh border, the Gower Peninsula and southern Pembrokeshire.
[35] Welsh speakers were keen for their children to learn English; knowing the language was felt to be a route to social mobility, made life more convenient and was a status symbol.
They believed it would contribute to Wales's economic development and that tenants or employees who could speak English would be easier to manage.
[40] The inquiry did not lead to any governmental action and the hostile reaction was mainly aimed at the comments about Welsh morality.
[14]: 96 Adults who experienced the Welsh Not as children recalled it with differing emotions; including anger,[41] indifference[42] and humour.
[43] In the late 19th and early 20th centuries various accounts were published of this method of discipline; which described it as having been used at an unclear point in the relatively recent past.
[47] The best-selling novel How Green Was My Valley (1939) by Richard Llewellyn includes an emotive description of the practice; "... the board dragged her down, for she was small, an infant ...
[58] Japanese musicians also created a short film, inspired by the similarities between the history of Okinawan dialect tags and the Welsh Not.