What the main keyboard layouts are, why they exist, how much difference they actually make to speed, and which one you should learn to type on. Short answer: the one under your fingers.
QWERTY is the layout on almost every English-language keyboard and most others besides, named for its top-left letters. AZERTY, used in France and Belgium, swaps A with Q and Z with W, moves M next to L, and puts the digits on the shifted layer so that accented letters get the unshifted number row. QWERTZ, used in Germany, Austria and much of central Europe, swaps Y and Z — Z is far more common in German — and gives dedicated keys to Ä, Ö and Ü. Each is a good fit for its language's letter frequencies and a poor fit for programming, where AZERTY and QWERTZ hide the brackets behind AltGr.
Arabic keyboards are usually printed alongside a Latin layout and switch between the two; the Arabic 101 layout places the letters by frequency and shape rather than by any historical accident, and it is a different touch-typing course entirely.
Dvorak, designed in the 1930s, puts all the vowels on the left home row and the most common consonants on the right, so that roughly seventy per cent of keystrokes happen on the home row compared with about thirty on QWERTY, and the hands alternate more. Colemak, from 2006, keeps most of QWERTY's punctuation and the Z X C V shortcuts where they are, changes only seventeen keys, and achieves similar home-row figures — which makes it far easier to switch to. Workman, Norman and others refine the same idea.
Less than its advocates say and more than its critics do. Controlled comparisons find a few per cent difference between QWERTY and Dvorak for equally trained typists, and less finger travel, which some people find more comfortable over long days. What makes people fast is touch typing and practice; competition typists at 150 WPM and beyond use every layout. Switching costs several weeks at a fraction of your speed and leaves you slow on every other keyboard you meet, which is most of them.
The honest recommendation: if you already type well on QWERTY, stay. If you are learning from scratch and only ever use your own machines, Colemak is a reasonable choice. If you have wrist pain, look at your posture and key force before your layout.
The free course here runs on QWERTY, AZERTY, QWERTZ, Dvorak, Colemak and Arabic 101, with the on-screen keyboard and finger guidance matching the layout you set in your profile. The French, German and Arabic layouts come with courses in those languages, so the words you practise are ones you would type.
Start the free course