Complex sentence: As with other free constructions, the functor "T" is left adjoint to some forgetful functor, here the functor which sends each "K"-algebra to its underlying vector space.
Split into simpler sentences: As with other free constructions, the functor "T" is left adjoint to some forgetful functor. In this case, it's the functor which sends each "K"-algebra to its underlying vector space.