Lost Time Incident

There's an alien species that finds human voices incredibly erotic. They can't control themselves. The first astronauts to speak to them in greeting and open diplomatic channels got spattered in a sticky fluid that contains the young of the species. Couldn't clean up without murdering the young and causing an incident. Sticky for months until hatching.

Aliens say the humans should just keep their mouths shut. They bring it on themselves.

Astronauts on outpost in deadly fear of stubbing a toe and cursing. NASA teaches electronics, in-flight protocols, and now sign language to all outgoing explorers. Disposable telephonic gizmos are built and left on the alien planet, used to communicate for the brief window before the gizmo's location becomes a de facto nursery.