'has been learnt before' is correct and usable in written English.
It is used to describe something that someone or something has already learned or studied. Example: Mary has been studying English for a long time, so many of the words she came across in her reading material have been learnt before.
This was one of the lessons of the congressional attacks on the National Endowment for the Arts at the very end of the Cold War; but the lesson had been learned before, in a parallel episode, at the very start of the Cold War, an episode that defined the limits of what government could openly do in the practice of cultural diplomacy.
My test of formative causation was to have students learn random sequences of letters, test the students, provide a second set of randomly sequenced letters half of which had been learned before and half unseen sequences, and test again to see if recall on previously learned sequences was better than sequences learned only once.
Brahms's "Four Serious Songs", perhaps, or a Bach cantata, both of which he had been learning before he was ordered to put on a Wehrmacht uniform.
Fourth-century sculptors, led by Praxiteles, Scopas, and Lysippus, gathered and expressed the best of what had been learned before of anatomy, pattern, and composition; by adding emotional appeal they can be said to have achieved the logical culmination of the Classical tradition, in which Phidian sculpture in the 5th century was but one brilliant and influential episode.
The numbers of both errors were also reduced when learning a shift mapping for the second time, if another shift mapping had been learned before (p<0.05, Wilcoxon ranksum test).
Consolidating sleep at night, he says, provides a greater proportion of the slow-wave, restorative sleep that promotes brain development and reinforces what has been learned the day before.
He said of his production and the music's dynamic range in an interview for Electronic Musician, "I've been learning to bring things down before I even start.
Over the past few years, I've been learning to seek the story before making up my own, to open my eyes to needs that may be unspoken, and to meet those needs myself instead of waiting for someone else.
In humans, however, a previous report demonstrated that cerebellar lesions affect acquisition but not retention of conditioned eye-blink responses that had been learned naturally before the insult (Bracha et al., 1997).
Ashley Young had been learning the wing-back role impressively before his hamstring injury but there have also been plenty of occasions when Van Gaal's defenders have looked unsure when the team is set up with three centre-backs.
