Moving along with instrument performing in plain English (5-5)
I believe the answer is:
anglo-saxon
'plain english' is the definition.
'Anglo-Saxon' can be an answer for 'english' (Anglo-Saxon is an example). I'm not sure about the 'plain' bit.
'moving along with instrument performing' is the wordplay.
'moving' is an anagram indicator (letters are moved around).
'with' is a charade indicator (letters next to each other).
'instrument' becomes 'sax' (sax is a kind of instrument).
'performing' becomes 'on' (as in being on stage).
'along' is an anagram of 'anglo'.
'anglo'+'sax'+'on'='ANGLO-SAXON'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for anglo-saxon that I've seen before include "old language" , "British settler from the 5th century" , "Early British settler" .)