Ogham is an ancient alphabet that appeared in Ireland at least 1,600 years ago. It was used to inscribe Primitive Irish onto stone monuments, the oldest known form of the Gaelic languages.
The word ogham refers only to the form of the letters, while the letters themselves are known collectively as the Beith-luis-nin, these are the first three names of the letters in the ogham alphabet, in the same manner as the word alphabet derives from the first two names of the letters alpha and beta.
The ogham alphabet originally consisted of twenty distinct characters called feda “trees”, and arranged into four groups called aicme “families”. The different groups correlate the direction of the strokes.
B Group – Right side strokes – Aicme Beithe
|ᚂ||L||luis||flame/blaze or plant/herb|
H Group – Left side strokes – Aicme hÚatha
|ᚈ||T||tinne||metal bar, ingot|
M Group – Across strokes – Aicme Muine
|ᚋ||M||muin||neck, upper back|
A Group – Notches (vowels) – Aicme Ailme
Supplementary Group – Forfeda
Five additional letters called forfeda were introduced mainly in the manuscript tradition several centuries after the peak of ogham usage. They appear to have represented sounds felt to be missing from the original alphabet
|ᚘ||P, later IO||pín, later iphín||spine/thorn|
|ᚙ||CH/X, later AE||eamhancholl||twin-of-hazel|
Peith ᚚ, a late addition to the Forfeda, is a variant of Beith (B), with a phonetic value of [p]. It likely replaced Ifín ᚘ, one of the “original” five Forfeda. Prior to the addition of the Forfeda to the original twenty letters, both [p] and [b] were probably symbolised by the same letter: Beith.
Here we have two decorative symbols often used at the start and end of inscriptions, and also a space symbol to separate words.