Dancer from Ireland breaking into song endlessly (9)
I believe the answer is:
ballerina
'dancer' is the definition.
(ballerina is a kind of dancer)
'ireland breaking into song endlessly' is the wordplay.
'ireland' becomes 'Erin' (poetic name for Ireland).
'breaking into' is an insertion indicator.
'song endlessly' becomes 'balla' (I can't justify this - if you can you should give a lot more credence to this answer).
'erin' placed inside 'balla' is 'BALLERINA'.
'from' acts as a link.
Can you help me to learn more?
(Other definitions for ballerina that I've seen before include "Female dancer, could be prima" , "girl on point duty" , "Dancers" , "Danseuse" , "Female classical dancer" .)