Girl that is following South American (5)
I believe the answer is:
susie
'girl' is the definition.
'that is following south american' is the wordplay.
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'following' is a charade indicator (letters next to each other).
'south' becomes 's' (abbreviation).
'american' becomes 'US' (United States).
's'+'us'='sus'
'ie' after 'sus' is 'SUSIE'.
(Other definitions for susie that I've seen before include "Girl" , "Woman" , "Girl's name" , "Little Susannah" , "Tongue-twister sister sewing shirts for soldiers" .)