Although I can't speak Cantonese, I can recognize it when spoken. Mandarin and Cantonese differ in tones and phonetics (sounds used in making words. Mandarin basically has four tones while Cantonese has seven-eight tones. Both spoken Mandarin and Cantonese are completely different and seem like two different languages. For example, a Mandarin speaker might say, "gongxi facai" as a New Year's greeting, while a Cantonese speaker will say "gionghi hwatchoi" or something similar to this..