Currently, https://i.delta.chat/ and, more importantly, the invitation-link-webpages like https://i.delta.chat/#n=誰か are always in English, which is not understandable for most people; especially for people who learned a language that is not written with latin text, as their native language. It would be good if those pages would be translated.
Note: while common web-browsers usually offer automatic translation, that is most-commonly done by someone-elses-computer (usually Google’s); so this can indirectly be a privacy-issue too. Having the pages already translated, would (normally) prevent that.
Because the invitation-pages can often contain someone-elses personal information (usually their name), it may also be a good idea to prevent such browsers from offering to translate the page. For Chromium-based browsers, that can be done with the meta-tag google with the content notranslate, according to the documentation of Chromium.