There is a wide variation in the use of medial 'mh'.  For some words, e.g. 'dìomhar' (secret), 'sgamhan' (lung), all participants in the Survey used mh=v in the pronunciation.  Against this, with some words such as 'cumhang' (narrow), 'cumhachd', power', 'mh' is not pronounced as 'v' in any of the cases.

 

 Between these extremes, uses of 'mh' as 'v' appears in two main areas:

1) Lewis/Harris + Sutherland in varying degrees

2) Kintyre, Islay, Arran.

In the case of 'samradh' (summer), mh=v is used only in the southern area.

In the case of 'famhair' (giant), mv=v extends from the south west into Perthshire, but is not found in Sutherland.  There does not appear to be a case where mh=v is used in the northern area but not in the southern.

 

Although there are apparent similarities between north and south, there are other differences e.g in the northern areas, 'sleamhainn' is pronounced using an 'a' vowel as compared to 'è' or 'é' in the south (as in French).  Those few examples in or near the Great Glen use the 'a' vowel, suggesting they belong to the northern group.

For those districts not employing the mh=v sound, there are many variations, one of which is the use of a glottal stop (shown on the map as '?')  For both 'sleamhainn' and 'gainmheach', the feature' is seen in Mull, Morvern and near Loch Linnhe.  It may be a transitional use between the 'v' sound of the southern area and the 'au' or 'w' sounds further north.  The same feature is observed in the same areas in some 'bh' medial examples  (see below).