Partner started receiving ads in foreign language they don't speak

I'm learning a language, I speak it in public to other people who do. I don't research the language, because I have some old text books on it. My partner doesn't speak it and doesn't research it on their devices. I don't normally have my phone on me in public, but my partner does. It took about 4 months of publicly speaking in the language before they got ads

What do you think this means?

::edit::

It was a Reddit ad and my city has embraced those AI smart cameras, so I assume some of those are Google owned which makes sense with Reddit and Google's recent alliance. This is assuming our devices aren't listening to us without our permission and AI cameras are mining data on passersby

Other theories are that since cellphones are involved it doesn't matter if I nor my partner ever searched for the language, at some point my phone or partner's phone was near someone who spoke that language and the data brokers/ad sellers inferred from there

Seems like the consensus is that I must have posted in the language on some social media or used Google to research it or made some new friends who speak the language and that's why