WHAT TO SAY

1. When starting to do something: "Bismillahir Rahmanir Raheem."

(In the Name of Allah, the Compassionate, the Merciful.)

2. When reaffirming one’s faith. “Laa Ilaahaillallah.” (There is no god except Allah.)

3. When praising something say, "Subhanullah." (Glory to Allah.)

4. When in pain or distress. "Ya Allah." (O Allah.)

5. When appreciating something say, "Masha-Allah." (As Allah willed.)

6. When thanking someone. "Jazakullah." (Allah reward you.)

7. When you see something bad. "Nowthzubillah." (Allah protect us.)

8. When saying you're sorry to Allah for a sin. "Astaghfirullah." (Allah forgive.)

9. After sneezing or when you're happy about something. "Alhumdulillah." (Praise Allah.)

10. When meeting someone. "Assalamu 'alaykum." (Peace be upon you.)

11. Replying to the above greeting. "Wa 'alaykum assalam." (And upon you be peace.)

12. When hearing about a death or tragedy. "Inna lillahi wa inna ilayhi rajiun."

(To Allah we belong and to Him we return.)

13. When giving in charity. "Fee eemanullah." (In Allah's faith.)

14. When taking an oath. "Wallah." (I Swear to Allah.)

15. If someone sneezes and they say, "alhumdulillah," you reply with, "Yarhamakullah." (Allah have mercy upon you.) The sneezer will reply back, "Yehdikumullah" which means, "Allah guide you."

16. When mentioning something that will be done in the future. "Insha'llah." (If Allah wills.)

17. When you have nothing to say. “Allahhuakbar.” (Allah is the greatest.)

Reference:-

Guide To Islam For New Muslims