Uppercase Lowercase Counter

In ordinary English prose, uppercase letters make up somewhere around 2 to 4% of all characters — sentence openings, proper nouns, and the occasional acronym. A ratio well above that has a specific cause worth finding: a heading pasted in as all-caps, a product name written in caps by one contributor and title case by another, or a section that has drifted into emphasis-by-capitalisation.

All-caps text is harder to read than mixed case, and the reason is mechanical rather than aesthetic. Readers recognise familiar words partly by their outline — the pattern of ascenders and descenders — and capitalising everything flattens every word into the same rectangle, forcing letter-by-letter reading. The effect is small for a three-word button and substantial for a full sentence, which is why all-caps body text measurably slows people down.

Accessibility guidance goes further and recommends against all-caps for anything beyond short labels, partly for that legibility reason and partly because some screen readers interpret capitalised words as acronyms and spell them out letter by letter. If you want visual emphasis at that weight, apply it with CSS text-transform rather than by capitalising the source text: the styling still renders, but the underlying content stays readable to assistive technology and to anyone who copies it elsewhere.