YOU SAID:
my mom bought me a purple shell!
INTO JAPANESE
母が私に紫色の貝殻を買ってくれました!
BACK INTO ENGLISH
My mother bought me a purple seashell!
INTO JAPANESE
母は私に紫色の貝殻を買ってくれました!
BACK INTO ENGLISH
My mother bought me a purple seashell!
That didn't even make that much sense in English.