The content language determines:

• The spell-checking of the note, when in a browser. The desktop installation has a dedicated spellchecking section.
• Whether the text is displayed from right-to-left, for languages such as Arabic, Hebrew, etc.
• How typed quotes are automatically replaced (e.g. English uses “text”, whereas some languages use «text»).

Setting the language of a single note

To set the language of the content of a Text note:

• On the new layout, there is a language selector in the Status bar.
• On the old layout, go to the Ribbon → Basic Properties and look for the Language field.

Adjusting the list of languages

By default there will be no language configured, they can be configured by going to Options → Language & Region or by selecting the Configure languages item when setting the language.

Default content language

Notes that do not have a language of their own follow Options → Language & Region → Default content language. It is set to English initially, and can be set to any content language, or to Based on the application's language.

If a note has a language set, it always takes precedence over the default.