I recently heard from another aunt who wants to teach English to her soon-to-arrive niece or nephew. Susana is a librarian in Spain and English is not her native language, so she and I are in the same boat! I'm enjoying "meeting" (online) other aunties and caretakers who are hoping to teach a second language to a child even when they're non-native speakers.
Anyway, as a librarian, Susana is constantly on the look-out for educational websites that celebrate language. Here's one that she recommends: Europe of Tales. It's a collection of animated folk tales, myths, and legends that you can read and listen to in eight different European languages. The site even includes a glossary and activity suggestions for teachers/parents. Take a look!