There isn't an English word for "cousin", "aunt", or "uncle"? How did they refer to their not-quite-immediate family members before these foreign words were inserted in the language?
Actually, it's not quite the same -- in German, the word Säugling (literally: a "suck-ling", or one that sucks or nurses) still exists, but Baby is much more common. (While in English, I don't think any form of the former relationship names has survived.)
If you want to sound like a native speaker, don't shy away from well-established loanwords.
Similarly, don't try to use Schreibstube instead of Büro or Gesichtserker instead of Nase etc. I'm not even sure there are native words for Straße or Fenster.
Use Baby. Use Party. Use Handy.
Perhaps you don't have to say Weekend.
If you're like me and think that English is a winsome speech that doesn't need to be dirtied with Latin loanwords, the true English word for ....
That's how you would come across if you try to speak "actual German".
Whatever your thoughts on language purism: if you want to speak to German people, I recommend that you speak like they do, not with words that sound old-fashioned and unnatural to native speakers. (Would you really say "winsome" instead of "beautiful"? If not, why say Säugling instead of Baby?)
That's one of the numerous reasons I don't care for English, it's virtually a creole of Romance and Germanic languages, which causes it to have bizarre spelling and grammar and words that don't fit together properly. Aber leider, it is my native language and the global lingua franca.
I would definitely call myself a purist when it comes to language. I appreciate languages like Icelandic and Mongolian, ones that take in relatively few loan words. When you hear spoken Icelandic, you hear Icelandic, not Icelandic (Remix featuring English and French).