en_tn/psa/049/003.md

My mouth will speak wisdom

Here the word "mouth" refers to the whole person who speaks. AT: "I will speak wise words" (See: rc://en/ta/man/translate/figs-synecdoche)

the meditation of my heart will be of understanding

Here the word "heart" represents the mind and thoughts. The abstract nouns "meditation" and "understanding" can be translated as verbs. AT: "the thoughts upon which I meditate will help you to understand" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-abstractnouns)