All technologies.
The objective of this technique is to provide users with a mechanism for turning standard diacritical marks on or off.
Many languages use diacritical marks or diacritics to indicate the pronunciation of words or to help distinguish between words. Some languages may use diacritics to denote vowels, to indicate consonant doubling, to indicate the absence of a vowel or a consonant, or for other purposes. Although text without such diacritics can be readable, the addition of diacritics can improve readability.
A Web page in Hawaiian displays all diacritical marks by default and provides links that allow users to select the level of display of diacritical marks:
Visitors select the level they prefer, and this preference is stored into a session cookie. All subsequent pages during that same session have access to the cookie, and show or hide diacritics according to the selected level.
On the server side, content is stored with all diacritical markings. If a visitor prefers fewer or no diacritics, a server-side function replaces or removes diacritics as desired before sending the response.
Example at Hawaiian language online.
For any Web page in a human language that uses diacritical marks to distinguish between meanings: