Yan tan tethera
Yan Tan Tethera or yan-tan-tethera is a sheep-counting system traditionally used by shepherds in Northern England and some other parts of Britain. The words are numbers taken from Brythonic Celtic languages such as Cumbric which had died out in most of Northern England by the sixth century, but they were commonly used for sheep counting and counting stitches in knitting until the Industrial Revolution, especially in the fells of the Lake District. Though most of these number systems fell out of use by the turn of the twentieth century, some are still in use . Origin and development. Sheep-counting systems ultimately derive from Brythonic Celtic languages, such as Cumbric; Tim Gay writes: “[Sheep-counting systems from all over the British Isles] all compared very closely to 18th-century Cornish and modern Welsh". It is impossible, given the corrupted form in which they have survived, to be sure of their exact origin. The counting systems have changed considerably over time. A particularly common tendency is for certain pairs of adjacent numbers to come to resemble each other by rhyme (notably the words for 1 and 2, 3 and 4, 6 and 7, or 8 and  9). Still, multiples of five tend to be fairly conservative; compare "bumfit" with Welsh "pymtheg", in contrast with standard English "fifteen". Use in sheep counting. Like most Celtic numbering systems, they tend to be vigesimal (based on the number twenty), but they usually lack words to describe quantities larger than twenty; though this is not a limitation of either modernised decimal Celtic counting systems or the older ones. To count a large number of sheep, a shepherd would repeatedly count to twenty, placing a mark on the ground, or move his hand to another mark on his crook, or drop  a pebble into his pocket to represent each score (e.g. 5 score sheep = 100 sheep). Importance of keeping count. In order to keep accurate records (e.g. of birth and death) and to be alert to instances of straying, shepherds must perform frequent head-counts of their flocks. Dating back at least to the medieval period, and continuing to the present in some areas like Slaidburn, farms were granted fell rights, allowing them access to common grazing land. To prevent overgrazing, it was vitally important for each farm to keep accurate, updated head-counts. Though fell rights are largely obsolete  in modern agriculture except in upland areas, farms are often subsidised and taxed according to the quantity of their sheep. For this reason, accurate counts are still necessary, and must be performed frequently. Generally, a count is the first action performed in the morning and the last action performed at night. A count is made after moving the sheep from one pasture to another, and after any operation involving the sheep, such as shearing, tagging, foot-trimming, mulesing, etc., although sheep are far less likely to stray while being moved in a group than when grazing at large on open  ground. Knitting. Their use is also attested in a "knitting song" known to be sung around the middle of the nineteenth century in Wensleydale, Yorkshire, beginning "yahn, tayhn, tether, mether, mimph". Modern usage. The counting system has been used for products sold within Northern England, such as prints, beers, hard seltzer, and yarns, as well as artistic works referencing the region such as Harrison Birtwistle's 1986 opera "Yan Tan Tethera". Section::::"Yan" or "yen". The word "yan" or "yen" for "one" in Cumbrian, Northumbrian, and some Yorkshire dialects generally represents a regular development in Northern English in which the Old  English long vowel <ā> was broken into /ie/, /ia/ and so on. This explains the shift to "yan" and "ane" from the Old English "ān", which is itself derived from the Proto-Germanic "*ainaz". Another example of this development is the Northern English word for "home", "hame", which has forms such as "hyem, yem" and "yam" all deriving from the Old English "hām". Systems by region. Wilts, Scots, Lakes, Dales and Welsh. "Note: Scots here means "Scots" not "Gaelic""