Aside from the official forms of their respective languages, the four linguistic regions of Switzerland also have their local dialectal forms. The role played by dialects in each linguistic region varies dramatically: in the German-speaking regions, Swiss German dialects have become ever more prevalent since the second half of the 20th century, especially in the media, such as radio and television, and are used as an everyday language, while the Swiss variety of Standard German is almost always used instead of dialect for written communication (c.f. diglossic usage of a language). Conversely, in the French-speaking regions the local dialects have almost disappeared (only 6.3% of the population of Valais, 3.9% of Fribourg, and 3.1% of Jura still spoke dialects at the end of the 20th century), while in the Italian-speaking regions dialects are mostly limited to family settings and casual conversation.

How many linguistic regions of Switzerland have their own form of local dialect?