The four official national languages – German, French, Italian, and Romansh – are spoken in dialects that often differ significantly from their written counterparts. 

Swiss German

Swiss German, encompassing a diverse range of Alemannic dialects, is the most widely spoken language in Switzerland. These dialects are spoken by the vast majority of the population in the German-speaking regions and are used as the everyday language across all settings and social classes.

There are significant dialect variations between different regions (e.g., Basel, Zurich, and Bern). Furthermore, numerous dialect subgroups can be found within the major language regions. However, all Swiss German speakers can understand each other.

Some dialects, such as the Upper Valais dialect in the German-speaking part of Valais canton or 'Seislerisch' in the German-speaking region of Fribourg canton, are characterised by strong regional features and distinct accents.

Apart from informal communication like text messages, Swiss German is not a written language. Standard German is used for written correspondence, and young children only begin to learn standard German when they start school.

French

In French-speaking Switzerland, French serves as the official national language. While each region has its unique characteristics and accents, Swiss French differs only slightly from standard French.

Franco-Provençal dialects (patois) were widespread until the mid-20th century but have almost disappeared today. However, they are still spoken by primarily older individuals in some valleys of Valais, the Jura, and the canton of Fribourg.

Italian

Italian is the official national language in Ticino and the southern valleys of Graubünden (Valle Mesolcina, Val Calanca, Val Bregaglia and Val Poschiavo). Swiss Italian originates from the Lombard dialect family and is influenced by other Swiss national languages and regional characteristics.  Italian dialects in Switzerland are highly diverse and often challenging for even Italian speakers to understand. Like Swiss German, they are typically only used in their spoken forms.

Romansh

Romansh is spoken by only a few tens of thousands of people in specific areas of Graubünden. It comprises five distinct dialects: Sursilvan, Sutsilvan, Surmiran, Puter and Vallader. Romansh speakers in Graubünden are not isolated; similar Romansh-speaking minorities can be found in the Italian regions of Friuli and South Tyrol.