Switch the page to another language through the language menu (#language_menu). The language is named by its label in the menu ("Deutsch"), its title ("German") or its hreflang ("de-DE"). A language the current page is not translated into is plain text, not a link, and the step says so.
Examples
When I switch to the "Deutsch" language
When I switch to the "Dansk" language
When we switch to the "English" language
And I switch to the "de-DE" language
When switch to the "German" language
Pattern
When(/^(I |we )*switch to the "([^"]*)?" language$/, …)
Part of @webship-js/typo3-steps (github.com/webship/typo3-steps), a step pack for Webship-js 2.0.x.