IPA: /ˈɪnfənsi/
KK: /ˈɪnfənsi/
The early stage of life or development, especially for babies and young children.
The technology is still in its infancy, and many improvements are expected in the future.
Infancy is formed from "in-" (meaning not) and "fancy" (from Latin "fari", meaning to speak). The term originally referred to a stage of life where one is not yet able to speak, thus denoting the early period of a child's life.
Think of a time when a child is 'not' ('in-') able to 'speak' ('fari') — that's why infancy refers to the early stage of life before speech.