The Alphabet Basics was divided into five groups of five letters. The groups were probably assigned to the North, South, East and West, with five-letter dates (Forfeda) associated with these mystical fifth Central Point. The whole oghmic system is in Irish Gaelic (ERSE), and its sub-systems depend on nominal tie in that language. Dozens of categories make up the correspondences (birds, colors, animals, lakes, water wells, battles, hills, rivers, etc.). Yet the correspondence was not met specifically mnemonic (eg-for ‘Fearn' Irish alder tree, it is the letter F, being it’s correspondence, the bird 'Faelinn' (gull), while in Celtic mythology is associated with the ' Raven, we can relate how many variants could be added to the secret encryption).
The Tree Alphabet is associated wiht the Beth Luis Nion a divination system from the first three sacred trees: the birch, rowan and ash. This system was compiled by Roderick O'Flaherty and is considered a relic of ancient druidism. As you may have noticed the thirteen original consonants in the ogmic alphabet are related to the thirteen months of the lunar and tree druidic calendar, these lunar calendars are similar to those of other cultures such as Mayan. The annual cycle was beginning in November since on the night of October 31 began the Celtic new year, Samhain, or End of Summer. It was joined by other eight trees and shrubs, namely: aspen, honeysuckle, apple, beech, white currant, Rose, and elm