A learner takes an alternative viva voce (4)
I believe the answer is:
oral
'viva voce' is the definition.
(synonyms)
'a learner takes an alternative' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
'learner' could be 'l' (as in a learner driver with L-plates on their car) and 'l' is found within the answer.
'alternative' could be 'or' and 'or' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for oral that I've seen before include "Relating to the mouth - exam" , "Concerning the mouth" , "By word of mouth, like some exams" , "Like some tradition" , "'Spoken, not written (4)'" .)