"I am thinking of things that begin with the letter" . . . D

Dumb (Tweedle)
Duck
Donut
  Disc
Dare
  Darling
Diddle
  Dunk
Doolittle
  Door
Draft
Disco
   Dent
Dashboard
  Desk
Dentures
    Dandelions
  Damper
    Dill
Deliberate
Day
   Daffodil
Dee (Tweedle)