Of more general importance is the fixing of boundaries for sound changes or inflexions that affect a large number of words, a task to which interesting contributions have been made in recent years on the evidence of place-names (see especially A. Brandl, _Zur Geographie der altenglischen Dialekte_, Berlin 1915, which supplements the work of Pogatscher on the compounds of _street_ and of Wyld on the ME. developments of OE. _y_). For example, on the evidence available, which does not permit of more than rough indications, OE. _ā_ remains _ā_, and does not develop to _ǭ_, north of a line drawn west from the Humber (§ 7 b i); _-and(e)_ occurs in the ending of the pres. p. as far south as a line starting west from the Wash (§ 13 ii); farther south again, a line between Norwich and Birmingham gives the northern limit for _Stratton_ forms as against _Stretton_ (§ 8 iv, note).[30] The direction of all these lines is roughly east and west, yet no two coincide. But if the developments of OE. _y_ (§ 7 b ii) are mapped out, _u_ appears below a line drawn athwart from Liverpool to London, and normal _e_ east of a line drawn north and south from the western border of Kent. Almost every important feature has thus its own limits, and the limits of one may cross the limits of another. [Foot-note 30: The evidence of place-names does not agree entirely with the evidence of texts. _Havelok_, which is localized with reasonable certainty in North Lincolnshire, has _(a)dradd_ in rimes that appear to be original, and these indicate a North-Eastern extension of the area in which OE. _strǣt_, _drǣdan_ appear for normal Anglian _strēt_, _drēda(n)_. This evidence, supported by rimes in Robert of Brunne, is too early to be disposed of by the explanation of borrowing from other dialects, nor is the testimony of place-names so complete and unequivocal as to justify an exclusive reliance upon it.] What then is a ME. dialect? The accepted classification is { South-Western = OE. West Saxon Southern { { South-Eastern = OE. Kentish { East Midland } Midland { } = OE. Mercian { West Midland } Northern = OE. Northumbrian with the Thames as boundary between Southern and Midland, and the Humber between Midland and Northern. And yet of five actual limiting lines taken at random, only the first coincides approximately with the line of Humber or Thames.