Question: The Northumbrian Dialect was spoken in a kingdom whose name reflects what approximate southern limit to the kingdom's territory?

Context paragraphs:
North American Arctic: The North American Arctic comprises the northern portions of Alaska (USA), Northern Canada and Greenland.  Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean.  The western limit is the Seward Peninsula and the Bering Strait.  The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.

English of Northumbria: The Northumbrian language or Northumbria English is an English language or dialect of English (""Northumbrian Language"" may only refer to the broadly spoken Northumbrian whereas Northumbrian English may just refer to the Standard English as spoken in Northumbria and featuring various Northumbrian words and forms), and a variant of Northern English with the Geordie dialect being one of the subsets of Northumbrian the others being Northern (north of the River Coquet), Western (from Allendale through Hexham up to Kielder), Southern or Pitmatic (the mining towns such as Ashington and much of Durham) Mackem (Wearside), Smoggie (Teesside) and possibly also Tyke (Yorkshire).  It is spoken mainly if not exclusively in the modern day counties of Northumberland and Durham.  Whilst all sharing similarities to the more famous Geordie dialect and most of the time not distinguishable by non-native speakers, there are a few differences between said dialects not only between them and Geordie but also each other.

Gawali Dialect of Melghat: It was thought that Ahirani or Khandeshi dialect is spoken in Old Khandesh district.  Now old Khandesh District of Maharashtra is divided in several districts.  Those are Jalgaon district, Dhulia District, Nandurbar district, Part of Nasik District and part of Aurangabad District.  Ahiras spoke Ahirani dialect.  Ahir Wani means dialect of Ahiras.  Wani means dialect.  It is known as Ahirani as it was spoken by Ahiras.  Same dialect in this region is known as Khandeshi dialect.  Because it is dialect of old Khandesh district.  Khandeshi is regional name and Ahirani is social name for same dialect.  Ahirani was spoken within the basin of Satpura Range and Sanhyadri Range.  High picks of Satpuda, of Sanhyadri range (Chandwad and Ajanta) did not allowed to spread this dialect out of this closed area of Khandesh District.  But similar dialect having similar social rituals, similar lexicography, phonology and syntax newly foundout by Dr. Ramesh Suryawanshi in Melghat area of Amaravati district.  Near about fifty villages where Gawali people reside speak Gawali dialect.  This dialect was not included in Griererson's Survey of India or Dr. Ganesh Devi's recent Bhasha Surveykshan.  Gavali dialect and Ahirani dialect are same and one.  Ahiras of Khandesh as well as Gawali of Melghat claim as they belong to God Shri Krishna's family.  Both having back history of having relation with Ashirgad Fort, and Goddess Asha Devi.  Both are cowherds indulged in business of milk and cattle.  Gawali's of Malghat are not literate and reside in forest.  Ahiras reside in towns and villages which are connected to metrocities with roads and railways.  Ahiras left most of their past rituals and traditions.  Ahiras of Khandesh nowadays are known by their business where as Gawalis are milkmen and cowherds. Most of their surnames are different.  Gavali's of Melghat give milk and milk products free of cost to villagers with rotation as per their Surnames.  It is considered that Gawali famili of Shaniware Surname should distribute milk and milk products free of cost on Saturday.  ( Shaniwar is word for Saturday )Gavali reside in Paratwada, Chandur, Melghat, Amarwati, Yeotmal Chimur tehsils of Vidarbhs Region.  A legend discloses history of Gawali's migration to Melghat area.  Lord Krishna went to Kaundanyapur with these Gawalis along with their several cattle.  As lord Krishna returned with his beloved Rukmani from Kaundannyapur.  Some Gawalis with their cattle decided to reside therein Melghat area as it was rich grassy land, good for their cattle.  This legendary story discloses the fact that Ahiras of Khandesh and Gawalis of Melghat both are of same race.  So their dialect is same and one.  This face is just disclosed by Dr. Ramesh suryawanshi in his article published in Critical Enquiry Vol.VI Issue IV.  Oct.- Dec. 2014 by Institute of Knowledge Engineering.

English language in Northern England: The English language in Northern England has been shaped by the region's history of settlement and migration, and today encompasses a group of related dialects known as Northern England English (or, simply, Northern English in the United Kingdom).  Historically, the strongest influence on the varieties of the English language spoken in Northern England was the Northumbrian dialect of Old English, but contact with Old Norse during the Viking Age and with Irish English following the Great Famine have produced new and distinctive styles of speech.  Some "Northern" traits can be found further south than others: only the northernmost accents of Northumberland and Tyneside retain the pre-Great Vowel Shift pronunciation of words such as "town" ( , ""toon""), but all northern accents lack the – split, and this trait extends a significant distance into the Midlands.

Wedderburn, New Zealand: Wedderburn is a community in Central Otago, New Zealand.  It is located 15 kilometres northwest of Ranfurly, and was at one time close to the centre of a thriving gold and coal mining area.  The name of Wedderburn was given to the area by John Turnbull Thomson, and is one of the names in his infamous "Thomson's Barnyard", wedder being Northumbrian dialect form of the word , meaning a castrated sheep.

Kingdom of Northumbria: The Kingdom of Northumbria ( ; Old English: "Norþhymbra rīce" , "kingdom of the Northumbrians") was a medieval Anglian kingdom in what is now northern England and south-east Scotland, which subsequently became an earldom in a unified English kingdom.  The name reflects the approximate southern limit to the kingdom's territory, the Humber estuary.

Galičnik dialect: The Galičnik dialect (Macedonian: Галички дијалект , "Galički dijalekt") or Mala Reka dialect (Macedonian: Малорекански дијалект , "Malorekanski dijalekt") is a member of the subgroup of western and north western dialects of the western group of dialects of the Macedonian language.  The dialect is spoken on small territory on the mountain Bistra in western part of the Republic of Macedonia.  The name of the dialect is derived by the biggest village in that area- Galičnik.  Also the dialect is spoken in many other small villages including the village Gari.  The Galičnik dialect is closely related with the Reka dialect which is spoken north-western of Galičnik dialect.  This dialect is well known in Republic of Macedonia because of the archaic words that this dialect has.  The dialect can be found in many historically important literary works for the Macedonian literature.  One of the most important is Ǵorǵija Puleski and his dictionary of three languages.

Ēostre: Ēostre or Ostara (Old English: "Ēastre" ] , Northumbrian dialect "Ēostre " ] ; Old High German: "*Ôstara" (reconstructed form)) is a Germanic goddess who, by way of the Germanic month bearing her name (Northumbrian: "Ēosturmōnaþ "; West Saxon: "Ēastermōnaþ "; Old High German: "Ôstarmânoth" ), is the namesake of the festival of Easter in some languages.  Ēostre is attested solely by Bede in his 8th-century work "The Reckoning of Time", where Bede states that during "Ēosturmōnaþ " (the equivalent of April), pagan Anglo-Saxons had held feasts in Ēostre's honor, but that this tradition had died out by his time, replaced by the Christian Paschal month, a celebration of the resurrection of Jesus.

Northumbrian dialect: Northumbrian was a dialect of Old English spoken in the Anglian Kingdom of Northumbria.  Together with Mercian, Kentish and West Saxon, it forms one of the sub-categories of Old English devised and employed by modern scholars.

Music of Northumbria: Here Northumbria is taken to mean Northumberland, the northernmost county of England, and County Durham.  This area, together with Tweeddale, was the ancient British tribal kingdom of Bernicia (Bryneich) and is notable for the stable ancestry of its present indigenous population, which has been identified by DNA analysis to be an offshoot of the group Scotland, Cumbria and the North of Ireland, but not so closely related to the other peoples of the UK.  The area was the core of the outstanding artistic culture that developed during the Northumbrian Golden Age of the 7th and 8th centuries; it would be unwise to suggest that the area did not have a flourishing musical culture at that time, or that it was not of similar sophistication - Bede makes reference to the playing of the harp.  The traditional music of this area may be a tangible legacy of the Bernicians - given that little is known of the antiquity of Northumbrian music; though traditional Northumbrian instruments would have had their limitations.  However, much surviving early modern Northumbrian music is similar in form to the music of the Scottish Lowlands, so Northumberland's position on the cultural frontier between England and Scotland has played a significant role.  The modern era has seen Northumbrian traditional music artificially pigeon holed into national divisions, into which Northumbrian music simply will not fit.  Likewise, the crude assumption that the font of all music of substance was in the west and north of the British isles has undermined considered appreciation of the local repertoire.The region possesses a distinctive style of folk music with a strong and continuing tradition.  The region is particularly noted for its tradition of border ballads, the Northumbrian smallpipe (a form of bagpipe unique to north-east England) and also a strong fiddle tradition in the region that was already well established in the 1690s.  Northumbrian music is characterised by considerable influence from other regions (and vice versa), particularly southern Scotland and other parts of the north of England.  Irish tunes are also much played in the region, as they are elsewhere.  There has been a continuous tradition of traditional and distinctive Northumbrian styles since the 18th century – there have also been 'revivals' in the late nineteenth century and again in the mid-twentieth.  More recently, Northumbrian folk music, and particularly the use of the Northumbrian pipes, has become one of the liveliest and most widely known forms of folk music in Britain.

Supporting paragraphs: Northumbrian dialect Kingdom of Northumbria
Answer: the Humber estuary