Kind speech is a rewarded charity. The Prophet ﷺ said: “A good word is charity.” (al-Bukhārī). And: “Guard yourselves against the Fire, even with half a date; and whoever cannot, then with a good word.” (al-Bukhārī).
العربية: عن أبي هريرة رضي الله عنه عن النبيّ ﷺ قال: «الكلمة الطيّبة صدقة». (البخاري). وقال: «اتّقوا النار ولو بشقّ تمرة، فمن لم يجد فبكلمةٍ طيّبة». (البخاري).
Speak kindly, encourage, greet warmly — a good word is a charity that costs nothing and earns much.