A voltage translator is used between two devices with different signal level, for example a 3v device and a 5v device, it translated the signal from one level to the other so the devices can communicate.
A voltage regulator can regulate the output to the specified voltage , it is usually referred to a power supply.
In addition to the difference mentioned by Alexan, I think that voltage translators are limited in their current capabilities. On the other hand, voltage regulators have large current capabilities as they can power a complete board.
Voltage regulators are mainly used for power supplies to produce a smooth, non-fluctuating DC while voltage translators are used for interfacing signals. They are almost the same, a voltage regulator can be sometimes used as voltage translator.
I agree with alexan_e
Voltage translation is required when microprocessors and peripheral devices operate
at different voltage levels within a system.
Voltage translators interface between these system components and solve
the problem of I/O voltage level incompatibility while retaining signal integrity.
Voltage translators can be used in any application where an interface is needed between system components
with different I/O levels.
Voltage regulation is the ability of a system to provide near constant voltage over a wide range of load conditions.
Voltage regulator is an electrical circuit designed to automatically maintain a constant voltage level.
A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops.
It may use an electromechanical mechanism, or electronic components.
Depending on the design, it may be used to regulate one or more AC or DC voltages.