Change Language Settings
Preceden's menus, buttons, and dialogs are only available in English. If they appear in another language, your browser is translating the page for you. To get Preceden to display in English again, change your browser's preferred language to English.
To do this in Google Chrome, click the menu icon (three vertical dots) in the top right corner and go to Settings. Click Languages in the left sidebar, or paste chrome://settings/languages into the address bar. Click Add languages if English isn't already in the list, then click Add. Once it's added, click the three dots next to it and select Move to top so it appears at the top of the list:

These directions may change or be different in other browsers. You can always search Google or YouTube for videos on how to change your browser's language settings.
Dates in another language
Each timeline has its own Language setting, which controls the language of the dates on the timeline, in the list below it, and in the date picker. Preceden picks it automatically when the timeline is created, and changing your browser's language afterward won't change it.
To show a timeline's dates in English, click the Appearance button above your timeline, open the Date Format section, set Language to English, and click Save Changes. See Date Formats for more about this setting.