How to say words like CERTAIN and MOUNTAIN | Glottal Stop, Glottal T

https://www.clearenglishcorner.com/blog/GlottalStop_GlottalT

20 Common Words Native Speakers Pronounce with a Glottal Stop: 1. Certain: Are you certain about that? 2. Mountain: I have a mountain of laundry to fold. 3. Fountain: Let's meet at the fountain at noon. 4. Curtain: Can you close the curtain? 5. Threaten: Don't threaten me! 6. Written: When was this written? 7. Tighten: We need to tighten our security. 8. Eaten: I haven't eaten all day. 9. Gotten: I haven't gotten it yet. 10. Forgotten: It's already forgotten. 11. Brighten: I hope this brightens your day! (Makes your day better) 12. Kitten: What a precious kitten! 13. Frighten: I didn't mean to frighten you. 14. Rotten: That's a rotten deal. (A bad deal, not fair) 15. Mittens: I've lost my mittens! 16. Bitten: I was bitten by the neighbor's ferret. 17. Button: Don't press that button! 18. Cotton: I think this is made of cotton. 19. Manhattan: Have you ever been to Manhattan? 20. Important: It's not important.