camaruthil

As an engineer, translator, and American, I use both learnt and learned as an adjective. For instance, a person is learned (two syllables), while scientific material is learnt. "The learnt material is very important for the exam on Monday." This, however, is not to be confused with the past participle, which is always learned (which is one syllable and has been used almost exclusively for most of the twentieth century on): "I learned how to derive the Navier-Stokes equations, but the learnt method was dependent on several assumptions." OR "I learned how to derive the Navier-Stokes equations, but method learned was dependent on several assumptions."