There are 15 words that start with 'dipht'.
| diphthong | diphtheria |
| diphthongs | diphtherial |
| diphtherias | diphtheroid |
| diphthongal | diphthonged |
| diphtheritic | diphtheroids |
| diphthonging | diphthongize |
| diphthongized | diphthongizes |
| diphthongizing | |
Note: These 15 words that start with 'dipht' are found from the USA & Canada version of the tournament Scrabble word list.