can anyone tell me the exact wording of this quotation ?

[Amelia Dunbar]

dear All,
The quotation I have is a French translation and I need to have it in English 
for a paper I`m presenting. Does anyone have the original wording of :

"the child acquires a competence which indicates to him when to speak, when 
not to speak, and also of what to speak, with whom, at which time, where, how"

(In French it was like this : «l'enfant acquiert une compéténce qui lui 
indique quand parler, quand ne pas parler, et aussi de quoi parler, avec qui, 
à quel moment, où, de quelle manière.» )

thanks for your help
Harriet Dunbar.