Scots is a living language and, although the examples of modern Scots included in SND only date as far as the publication of the last part of that dictionary, in 1976, work has continued since then on collecting information on Scots usage.
wikipedia - List of Englishwords of Scotsorigin
wikipedia - List of Englishwords of ScotsGaelicorigin
Gaelic is the traditional language of the Scotti or Gaels, and the historical language of the majority of Scotland.
Gaelic has a rich oral (beul aithris) and written tradition, having been the language of the bardic culture of the Highland clans for several centuries, and the survival of Gaelic has been therefore a very important factor in Scottish politics.
Lowland Gaelic was spoken in the southern regions of Scotland prior to the introduction of Lowland Scots.