Lower groupsign
The “bb” contraction in braille
One cell for the letters “bb”, but only with a letter on each side of it.
Dots 2-3
Unicode ⠆ — written entirely in the lower part of the cell
How to recognise it
Dots 2 and 3 — the letter b slid down one row. It shares its cell with the be- prefix: at the front of a word the cell is be-, in the middle it is a doubled b. Rubber, hobby, ribbon, rabbit.
The same cell says other things
This is what makes the lower signs hard, and it is not a flaw in the code — there are sixty-three possible cells and far more than sixty-three things to write, so the busiest shapes do several jobs. Position is the whole of the distinction: bb is read where the rules below allow it, and one of these everywhere else.
It has to have a letter on each side
Both neighbours must be letters. A lower sign at the start of a word would be indistinguishable from punctuation opening a sentence, and at the end from punctuation closing one, so the rule bars both positions outright rather than asking the reader to guess.
It is the letter b moved down a row
Take the cell for b and slide every dot down one place — dot 1 to dot 2, dot 4 to dot 5 — and you have this sign. Every lower sign in braille is built that way, which is the reason the family is quicker to learn than eight unrelated shapes would be: you already know all of them, one row up. Most punctuation marks come from the same shift.
How often you will meet it
Of the 5,000 most common English words, 3 words use this sign. That is worth knowing before you spend time on it: the eight lower signs are not equally useful, and they range from 148 of those words down to 3. That is few enough to simply list: the table below is not a selection, it is every one of them. Recognise the shape when it appears and spend your practice time elsewhere.
The contraction list ranks the whole of Grade 2 the same way.
Every word that uses it
Every one of these is shorter in Grade 2 than in Grade 1. They were not chosen by hand: each was taken from the reference implementation's own output for the most common English words, and this site still writes every one of them the same way, cell for cell.
| Word | In braille (Grade 2) | Grade 1 | Grade 2 |
|---|---|---|---|
| rubber | 6 cells | 4 cells | |
| hobbies | 7 cells | 6 cells | |
| caribbean | 9 cells | 6 cells |
Words where it is written out instead
These contain the same letters and do not use the sign. Each one fails the rule for a different reason.
| Word | Written as | Why |
|---|---|---|
| bb | with nothing on either side there is no word for the sign to sit inside |
In a whole book
In a count over the whole of Alice’s Adventures in Wonderland (26,439 words), this contraction is written 66 times and saves 66 cells. That is 0.19% of everything Grade 2 saves in the book, and ranks it 88th of the 158 contractions used.
The words it is written in most: rabbit (47), rabbit's (4), nibbling (3), sobbing (3), nibbled (2) — 10 different words in all.
Check your own text
Type anything into the translator with Grade 2 selected and this cell will appear wherever the rules allow it. The full contraction list covers the rest of Grade 2, and the practice drill has a contractions mode that offers the cells one dot away from this one as the wrong answers.
The “bb” cell as an image
The cell is dots 2 and 3, with dots 1 and 4 empty. That empty top row is what makes a lower sign recognisable at a glance.
