While I am surely not perfect myself, I still found a spelling error in the TeamSpeak 3 client.

Considering that the core development team is German, I can imagine how this happened.

The error can be spotted when one edits a server, then click on the tab "Misc".

In the lower part it reads:
--> "Priority speaker dimm modificator"

In proper English, it should read:
--> "Priority speaker dim modifier"

"Dim" has only one "m" (except when using the progressive form "dimming") and the word "modificator" (possibly directly translated from German "Modifikator") does not exist in English. "Modifier" would be a better word in its place.