B4PPC is a weakly typed language and normal (non-array) variables are not really typed at all. They are saved as strings and all numeric calculations are done by converting them to and from floating point doubles. Booleans are actually strings with the values "true" and "false".
Arrays ARE typed but ONLY IF you declare them as such, otherwise they are like non-array variables. Calculations done using typed arrays can be somewhat faster than with ordinary variables or arrays as, while they are still converted to and from doubles for calculation, this is a faster process than string conversion.
A note about libraries for completeness, their existence being the reason that B4PPC needs to know about types. B4PPC knows about certain types, such as Color, Boolean, Int16 etc, and converts its' non-array variables to and from these types when a library requires it. Arrrays, to save processing time, are not converted when passed to a library and so must be declared within B4PPC to be whatever type a library requires.