Purpose of this from the WCAG guidelines about text-spacing

1. What is text spacing in accessibility?
2. Why is text spacing important?
3. What is the spacing between lines of text Why is this important in typography?

What is text spacing in accessibility?

Official wording in the Web Content Accessibility Guidelines

Line height (line spacing) to at least 1.5 times the font size; Spacing following paragraphs to at least 2 times the font size; Letter spacing (tracking) to at least 0.12 times the font size; Word spacing to at least 0.16 times the font size.

Why is text spacing important?

Like many micro-typographical parameters, letter-spacing has a decisive influence on the legibility of text: If the letter-spacing is too large or too small, the words may not be correctly comprehended, and the reader must spell out the text, which is painstaking.

What is the spacing between lines of text Why is this important in typography?

The traditional term for line spacing is leading (rhymes with bedding ), so named because traditional print shops put strips of lead between lines of type to increase vertical space. Sometimes you see this term in typesetting software. For most text, the optimal line spacing is between 120% and 145% of the point size.