t seems now to be agreed that the various dialects of Scottish Gaelic
fall into two main divisions--northern and southern. Mackinnon states
that the boundary between the two passes roughly up the Firth of Lorne
to Loch Leven, then across country from Ballachulish to the Grampians.
The country covered by the northern dialect was of old the country of
the Northern Picts, whilst the portion of Argyllshire south of the
boundary line, together with Bute and Arran, made up the kingdom of
Dalriada. The Gaelic district south of the Grampians belonged to the
Southern Picts. The southern dialect is commonly regarded as the
literary language. It approaches more nearly to Irish and preserves
the inflections much better than the speech of the north.

The following characteristics of the northern dialects may be
mentioned:--(1) The diphthongization of open e to ia is carried much
farther in the north than in the south. (2) The vowel ao in the north
is more regularly the high-back-narrow-unrounded vowel-sound, whereas
the south in many cases has a low-front-wide-round sound. (3) The
north has _str_ in initial position where the south prefers sr.
Further, the northern dialects go very far in dropping unaccented
final vowels. It may be remarked that in the reduction of derivative
endings containing long vowels Scotland goes hand-in-hand with Ulster
Irish, thus Connaught _aran_, "bread," is in Ulster and Scotland
_aran_. Again, Scottish agrees with North Irish in the loss of
synthetic verb-forms and in using as negative _cha_, Mid. Ir. _nico,
nocha_. But, on the other hand, Scotland, with the exception of South
Argyll and some of the Isles, diphthongizes accented a, o, e, in
monosyllables, before ll, nn, m, thus resembling the speech of
Munster. In South Argyll the original short vowel is half lengthened.

As to the southern limits of Gaelic speech in Scotland, the boundary
between Gaelic and English in medieval times was the so-called
Highland line, and at the War of Independence it is probable that it
extended to Stirling, Perth and the Ochil and Sidlaw Hills, the Inglis
being limited to a very narrow strip along the coast. Dr J.A.H. Murray
traced the linguistic frontier in 1869-1870 with the following
results. The line started about 3 m. west of the town of Nairn on the
Moray Firth and ran in a south-east direction to the Dee, 4 m. above
Ballater. On the other side