en_tn_condensed/psa/049/003.md

My mouth will speak wisdom

Here the word "mouth" refers to the whole person who speaks. Alternate translation: "I will speak wise words" (See: rc://en/ta/man/jit/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. Alternate translation: "the thoughts upon which I meditate will help you to understand" (See: rc://en/ta/man/jit/figs-metonymy and rc://en/ta/man/jit/figs-abstractnouns)