The mouth is synecdoche for the whole person. Alternate translation: "I will tell" or "I will speak with my mouth and tell" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
This can be restated to remove the abstract noun "righteousness." Alternate translation: "how righteous you are" or "all the good things you do" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
The abstract noun "salvation" can be stated as an action. Alternate translation: "how you have saved me" or "how you save people" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])