DAR has been recorded in textual form since 1673, and the orthographic representations "t'" and "th'" occur in literature (such as in Emily Brontë's Wuthering Heights) and are frequently encountered in the media.
A similar usage of an article with a consonant "t'" can also be found in Modern Dutch and in the West Frisian language off the north Netherlands coast.
In Cumbria, a voiceless alveolar plosive (the English t sound) occurs and may have some superficial similarities to realizations in West Frisian and Low German, but the glottal and the glottalised DAR variants that are found elsewhere in the DAR area and across Yorkshire present a very different realisation.
Jones (2002: 342) comments that no contact explanation with other varieties of Germanic is required (or could be supported on the basis of available evidence) to explain DAR as the development of DAR involves common cross-linguistic patterns of change (stopping of dental fricatives, change of plosive to glottal) that occur in unrelated languages and so they have a purely phonetic origin.
Instrumental acoustic work in 2007 showed that DAR speakers use very subtle differences in the quality and timing of glottalisation to differentiate between a glottal stop occurring as an allophone of final /t/ in a word like "seat" and a glottal stop occurring as the form of the definite article in otherwise identical sentences (compare "seat sacks" and "see t' sacks").