Is that with a "T" or "D"?

Gwen and I were in the car today and I got a glimpse into a 4 year old's language development.  I realized that kids mispronounce things not because they can't say certain sounds, but because they think it's spelled differently.  Maybe we adults needs to annunciate better!

Gwen:  "I have red marker on my sumb"

Me:  "Oh, you have red marker on your thumb?"

Gwen:  "On my sumb"

Me:  "How did you get marker on your thumb?"

Gwen: "How did you say it? Thumb?:

Me:  "Thumb"

Gwen:  "I thought it started with an S"

Me:  "Ha ha (laughing because I was so proud she recognized the sound difference and that she would think in those terms), no, it starts with a T-H.  Like in 'that'"

Gwen:  "Oh, I know something else that starts with T-H, froad"

Me:  "Float?  No, float starts with 'f'"

Gwen:  "No,not float, throad"

Me:  "Throat?"

Gwen:  "Yeah, throad"

Me:  "Throat like your neck?"

Gwen:  "No, it's inside your neck!"

Me:  "Oh, throat.  Yes, throat starts with TH"

Gwen:  "yeah, froad"

Me:  "throat"

Gwen:  "froat?  does it end with a D or a T?"

Me:  "It ends in T"

Gwen:  "froat."