so
咁 centers on the idea of 'so' or 'in this way', often used as a demonstrative adverb in Chinese contexts. Its meaning is narrow and functional.
咁 is a phono-semantic compound with 口 (mouth) and 甘 (sweet), but the exact historical development is uncertain. It likely originated as a dialectal character for 'so' or 'such'.
The mouth 口 speaks sweetly 甘, as if saying 'so' in agreement.
For カン, imagine a can of sweet words: can -> カン, and the mouth 口 speaks them so sweetly 甘.