How did they arrange the letters on the keyboard? - Answers

The letters are arranged by amount of use. The letters in the center row, directly below the fingers in the neutral position (a, s, d, f, h, j, k, l) are the most used letters in English, and moving up, down and in (g, h, e, r ,t y, u, i, c, v, n, m) are used a lot, but not as much as the keys in the neutral finger position. Then come the keys that sit on the outer edges (q, w, o, p, z, x and the punctuation keys) are the least used, and so are put in the least favorable positions. The reason that some frequently used keys are farther apart was initially not just to allow faster two-handed operation : on typewriters, metal bars holding the type had to move upward to strike the paper on the platen. If two keys were close together and hit too quickly (e.g. ER), their bars could hit each other as one went up and the other came back. Among other changes, it meant that 4 vowels (YUIO) were moved to the right, farther from the most-used consonants on the left and bottom row.