No official documentation exists for recording a baby's first words, as the vocalizations a baby makes are often a form of babbling rather than actual words. A baby learns to speak during his first two years by observing how his parents communicate.
A baby first expresses himself through crying. A piercing and loud scream may mean he is hungry, while a staccato-type whimper may mean he needs to be changed. Gurgles, coos and sighs are included in the repertoire.
Sounds can turn into words, such as "Mama," as soon as a baby turns 6 months old. Afterwards, an infant expands on his vocalizations and words. Between 18 months old and 2 years old, a baby typically starts to form two-word sentences.
By the time a baby reaches 13 months old, he is typically using and recognizing one or more words in his speech according to BabyCenter.