you cannot teach an old dog new tricks
Definition:  it usually is difficult for people to abandon their habits that they are used to
Usage:  Denver is always late at his new place of employment, because he is used to waking up late when he is still unemployed; after all, you can’t teach an old dog new tricks

SEPEDI
Translation:  o ka se rute mpša ya kgale malomelo a maswa
Proverb: thutelabogolo e a roba

XITSONGA
Translation:  u nge dyondzisi mbyana ya khale maendlelo mantshwa
Proverb: ku endza mukhalabya, jaha a ri endzi

TSHIVENḒA
Translation:  u nga si funze mmbwa ya kale maitele maswa
Proverb: mutukana ha endi, hu enda mukalaha