My infant is 11mts old with no sign of teeth?

That is fine. Children's teething can start as late as 15 month, normally they do two out of three early and one lat( talking, walking, teething) you can have him checked if you are worried.
Yes. Infants can have their first teeth present at birth or as late as 15 months. The later erupting group often get several erupting at one time.It is not an indicator of growth or nutrition problems but a variation of normal. Most have a full set of baby teeth by 3y.