What are the distinct stages, landmarks or milestones in language acquisition in regard to phonetic development? What is the order they're typically reached, and why is it that order?
For instance, I know that certain types of phonemes are learned at different times. Vowels are usually learned early, and different types of consonants are learned later.
I'm particularly interested in the why of these developmental stages. Phoneme acquisition charts are easily found, but they don't discuss why certain phonemes are learned before others. I understand it's likely rooted in physiological and/or neurological development, so that's what I'm interested in.
I'm asking primarily about English pronunciation and grammar, but would also be interested in info for the entire IPA.
While I'm not a linguistics student or professional, I'm comfortable with technical terms, such as those found in Articulatory Phonetics, Occlusives, Manners of Articulation and linguistic/grammatical terminology. I have access to resources about these areas of interest once I know where to look.
Age range can be assumed to be from start of speech until "mastery" of all landmarks. I'm not just interested in a single age, but the full breadth of development. (Unfortunately, I must be broad, since I don't know the individual stages, I can't right now ask about them individually).
I did ask nearly the same question on Parenting, but it was suggested I come here for a better answer.