Using the Ogham converter
Type English on the left and Ogham appears on the right, wrapped in the feather marks ᚛ ᚜ that open and close an inscription. Swap the boxes to read Ogham back.
The output is real Unicode, so it copies into a document and stays text. Any letter the alphabet has no sign for gets listed under the box rather than dropped.
An alphabet written along an edge
Ogham is cut along a line instead of sitting on one. On a standing stone that line is the edge of the rock, and each letter is one to five strokes placed right of it, left of it, across it at an angle, or straight through. You start at the bottom left and read upwards, turning the corner if the text runs long.
The design follows the tool. Strokes are fast to chisel and can be counted by touch in bad light, and using the stone's own edge means no ruled line to lay out first. On screen that edge becomes a character of its own, so Ogham needs a font that knows to draw it.
Ogham chart
Trees, Romans and 400 stones
The letters have names, and most of the names are trees: beith is birch, luis is rowan, coll is hazel. Medieval scribes built on that, arranging the alphabet as a grove and using the tree names to memorise it, which is where "the tree alphabet" comes from.
About 400 inscribed stones survive, most in Ireland with a scattering in Wales, Scotland and the Isle of Man. Nearly all carry the same thing: a name, and whose son the person was. Boundary markers and memorials, not literature.
Why it was invented is still argued over. One suggestion is that it grew up deliberately out of reach of Latin readers. The alphabet appears while Roman Britain is next door, it fits early Irish rather than Latin sounds, and it can be cut by someone who never learned Roman letters. Other scholars read the same evidence as ordinary borrowing.
Related conversions
Runes come from the same impulse: an alphabet shaped by the chisel rather than the pen. Both converters transliterate, so your words stay English underneath.
Morse is the version built for a wire instead of a stone, and it counts in time rather than strokes.
Questions
Why do I see boxes instead of strokes?
Your device has no Ogham font. This page bundles one, but text pasted elsewhere depends on that app having one too.
What are the marks at each end?
Feather marks, showing where an inscription starts and stops. They matter when writing runs up the edge of a stone and could be read from either direction.
Is Ogham a cipher?
No. It's a real alphabet used for inscriptions from roughly the 4th century. Later manuscripts do play with it as a way of writing in plain sight, which is closer to a cipher's job.
Can it write any English word?
Almost. The alphabet was built for early Irish, so a few English sounds take the nearest available sign. The converter says which ones it had to approximate.