In ordinary language, right in position (5)
I believe the answer is:
prose
'in ordinary language' is the definition.
'prose' can be an answer for 'language' (I have seen 'Ordinary language ' mean 'prose' so perhaps 'language' could also mean 'prose'). I'm not certain of the 'in ordinary' bit.
'right in position' is the wordplay.
'right' becomes 'R' (common abbreviation).
'in' means one lot of letters goes inside another.
'position' becomes 'pose' (posing is a kind of positioning).
'r' going within 'pose' is 'PROSE'.
Can you help me to learn more?
(Other definitions for prose that I've seen before include "Non-verse" , "Normal written language" , "Writings not in verse" , "Literary genre" , "Ordinary writing" .)