While most of us get tongue tied when we are overawed by a famous personality or when asked to speak in public, or too overcome by emotions, in the case of your infant, it could be due to the fact that the cord of tissue (called the frenulum) that holds the tongue in place against the floor of the mouth is too tight / thick / rigid.
This is probably one of the most common questions that I encounter. By the time this question comes up, I have already discussed about the near negligible risks (but not zero) of surgery and anesthesia in children at least twice. The actual risk of death for healthy children undergoing anesthesia is of the order of 1:100000 children undergoing anesthesia. To define this in easily understood terms, the risk is less than half the risk of crossing a busy street. We merrily (or should I say with gay abandon!) cross streets 15-20 times a day at the very least, paying nary a thought to the very real possibility of an accident.