Define naturalization.
Well, lets start at wiki:
Naturalization (or naturalisation) is the legal act or process by which a non-citizen in a country may acquire citizenship or nationality of that country.[1] It may be done automatically by a statute, i.e., without any effort on the part of the individual, or it may involve an application or a motion and approval by legal authorities
A baby just born is not a citizen of ANY country UNTIL that country accepts (via law) that child as a citizen. For example, India and Malta no longer recognizes jus soli as an automatic grant of citizenship.
The US has codified who is a citizen at birth and has provided the statue (via title 8 section 1401) that grants citizenship to those born on US soil, and those born abroad to US Parents with conditions.