RobH_en_tn/ecc/10/20.md

not even in your mind

A person's thoughts are represented by the person's "mind." Alternate translation: "not even in your thoughts" (See: rc://en/ta/man/translate/figs-metonymy)

rich people in your bedroom

"rich people when you are in your bedroom." This means that you should not curse rich people even when you are in a private place where no one else will hear.

For a bird of the sky ... can spread the matter

These two lines mean basically the same thing and are combined for emphasis. This speaks of people finding out what you have said as if a small bird would hear what you say and tell other people. Alternate translation: "For a bird may hear what you say and tell the matter to other people" (See: rc://en/ta/man/translate/figs-parallelism and rc://en/ta/man/translate/figs-metaphor)