Comparison of Irish, Manx, and Scottish Gaelic

[citation needed] The spoken dialects of Irish and Scottish Gaelic are most similar to one another in Ulster and southwestern Scotland, regions of close geographical proximity to one another.

It is thought that the extinct dialect of Galwegian Gaelic, spoken in Galloway in the far south of Scotland, was very similar to Ulster Irish and Manx.

For example, in both Munster Irish and the Gaelic of the north of Scotland, historically short vowels have been diphthongised or lengthened before fortis sonorants.

The closest to Scottish Gaelic in modern Irish is the dialect currently spoken in County Donegal, as illustrated by the sentence "How are you?".

The Classical Irish digraph ⟨éu⟩ [eːʷ] is still used in Scottish Gaelic spelling but is now obsolete in Irish, except in southern dialect writing, as a means to distinguish the vowel ⟨é⟩ when followed by a broad consonant from the regular dialect development ⟨é⟩ to ⟨i⟩ in the same environment, thus éan [ian] "bird" in comparison to d'éug [dʲeːɡ] "died; passed on).

At times Scottish writers used the spelling ⟨ia⟩ to represent how the combination is pronounced in northern dialects, writing ⟨ian⟩ instead of ⟨eun⟩, the southern form.

However, recent spelling reform has meant that only grave accents are now in Scottish Gaelic, leaving phonemic distinctions unmarked.

For example, "hill" and "mountain" are usually "cnoc" (Knocknapeasta) and "sliabh" (Slieve Donard) respectively in Ireland, but "càrn" (Cairn Gorm) and "beinn" (Ben Nevis) in Scotland.