This is the loss of unstressed vowel sounds in a word.  In 'bliadhna', it is the final 'a', in 'samhradh', the final 'adh' and in 'doras', the 'a' in the second syllable.

 

The maps show that this is a feature of Gaelic in the eastern Highlands, best seen in 'bliadhna', where the final 'a' is lost from northern Sutherland, through Strathspey, Perthshire and perhaps into Argyll. 

In the 'samhradh' map, the following coding is used:

samhrvc=no loss of schwa (v = vowel, c = consonant).

samhrvx=vowel from last syllable present but no final consonant

samhrxx  =loss of final syllable.

 

Further information of pronunciation of the first syllable of 'samhradh' has been dealt with above (see Medial 'mh'). 

It can be seen that the loss of schwa in 'bliadhna' corresponds quite well with the combined distributions of 'samhradh' with total or partial loss.

 

Total loss of schwa for 'samhradh' covers an area similar to but more extensive than that for 'doras', the latter being found to a limited extent in Speyside.   Grannd (2008) has suggested that similarities between the Gaelic of Rothiemurchus (on the north side of the Cairngorms) and that of Braemar on Deeside may be due to contact through the mountains via the Lairig Ghru - a well known walking route between Speyside and Deeside. It is therefore possible that the influx of this feature is due to Perthshire influence spreading northwards into Strath Spey.  However, it can be seen the loss of schwa was not reported in Braemar, though Watson and Clement (1981) write that 'dors' was used for 'dorus' in Aberdeenshire Gaelic.