infants produce a variety of vowel- and consonant-like sounds that they combine into increasingly longer sequences. the production of vowel sounds (already in the first 2 months) precedes the production of consonants, with the first back consonants (e.g., [g], [k]) being produced around 2–3 months, and front consonants (e.g., [m], [n], [p]) starting to appear around 6 months of age.