explain廣東話和普通話不同的地方和困難給 外國人

explain廣東話和普通話不同的地方和困難給 外國人
explain the difference of Cantonese & mandarin (Putonghua) and the difficulties for Cantonese to learn mandarin to foreigners in English
My foreigners friends think only Mandarin is Chinese. they dont consider Cantonese as chinese, when they know i dont speak mandarin, they think i don't speak chinese. i want to tell them to learn mandarin is different for us -Cantonese because there is spoken cantonese and written chinese writing. it is totally different. the Taiwanese or maninland chinese- they can write what they speak. but for us Cantonese, when speaking mandarin, we have to change our spoken langauage to written chinese.
Mandarin uses simplified chinese characters but cantonese use traditonal characters, and mandarin uses different phrasal verbs.