Sie sollten nicht so laut über manche Dinge reden!

English Translation

You should not speak so loud about certain things.

could this also be von?

1 Like

Yes, it’s the same as in english:
speak about things <-> speak of things

with the same minimal difference.
When you speak “über”/“about”, then “Dinge” is the general topic.
When you speak “von”/“of”, then you’re sharing your personal experience.

However, with “von” the case changes from accusative to dative:
über manche Dinge reden
von manchen Dingen reden