Anthony has you covered for infant / toddler / child.
There really isn't much difference semantic between "stage" and "phase". It's probably mostly a difference of collocation. [Collocation means that some words usually go together, like "diet coke" and "light beer" -- you wouldn't say "light coke" or "diet beer" even though they would mean the same thing. Another example of collocation is "freedom" and "liberty" which mean the same thing. But you always say "freedom of the press" and never "liberty of the press". This kind of linguistic habit is called collocation.]
The stages of language acquisition, the stages of life, the stages of growth, but the phases of the moon. If you want to see more collocations, simple do a google search on "the stages of" and "the phases of".
3) remember, remind
Remembering is what you do, Reminding is one someone does for you.
I remember when I was a child. Can you remind me what happened when I was a child?