Writing
Writing is built left-to-right in single rows, preferably surrounded by one layer of blocks on all sides, perhaps built into a wall.
Alphabet
1 - A - Cobblestone Block
2 - B - Stone Block
3 - C - Stone Brick Block
4 - D - Cobblestone Slab (lower)
5 - E - Stone Slab (lower)
6 - F - Stone Brick Slab (lower)
7 - G - Cobblestone Slab (upper)
8 - H - Stone Slab (upper)
9 - I - Stone Brick Slab (upper)
10 - J - Cobblestone Stair (left)
11 - K - Stone Stair (left)
12 - L - Stone Brick Stair (left)
13 - M - Cobblestone Stair (back)
14 - N - Stone Stair (back)
15 - O - Stone Brick Stair (back)
16 - P - Cobblestone Stair (right)
17 - Q - Stone Stair (right)
18 - R - Stone Brick Stair (right)
19 - [space] - Word delimeter.
20 - [double space] - Sentence delimeter.