Answer:
Dr. Patricia K. Kuhl found that the babies' brains are most open to learning the consonants in their native language at nine months old and vowels at six months old.
Step-by-step explanation:
Dr. Patricia Kuhl identified that babies, at six months of age, have a great capacity for learning even two languages while allowing them to analyze the correct intonation and accent of them, although between three and five months the babies can capture the sound of some vowels or even consonants, her study showed that at six months it is the ideal age to learn vowels of one or two languages and that at nine months it is in perfect condition to learn consonants in general.