Japanese vs Cantonese
Should I learn Japanese or Cantonese?
Japanese and Cantonese are unrelated, but Japanese kanji and Cantonese Traditional characters overlap heavily, and Cantonese pronunciation of many Sino-Japanese words is closer than Mandarin's because both preserve old final consonants.
The short answer
Choose Japanese for a bigger media world, a toneless sound system and Japan; choose Cantonese for Hong Kong, Macau, Guangdong or family heritage. Both are in the FSI's hardest category, and Cantonese has far fewer learning resources.
The verdict
Pick Japanese for media and structured resources; pick Cantonese for Hong Kong life.
Closeness score
7 / 30
Mutually intelligible?
no
Shared vocabulary
Many shared character compounds; spoken overlap small
Which first?
No strong order effect.
Kungfucius says: Kanji learners: Cantonese hears the -k in 學 that Mandarin forgot.