This dissertation is a cross-linguistic study on how Mandarin Chinese-speaking and Seoul Korean-speaking children develop the capacity for prosodic focus-marking in their speech production. We collected and analysed semi-spontaneous production of sentences from four- to eleven-year-olds and adults in both languages. We have seen that which prosodic focus-marking means is acquired first in a language depends on what is the primary prosodic focus-marking means in the language. Furthermore, we have seen evidence showing that the presence of lexical use of a prosodic property in a language influences the rate and route of the acquisition of prosodic focus-marking in the language. Our findings suggested that the developmental path to adult-like prosodic focus-marking is shaped by both the prosodic system and prosodic focus-marking system.