The IPA has a diacritical mark that it placed underneath those symbols
to specify that they are dental. It looks like a box without a bottom.
-R
Nikhil Sinha wrote:
> I have a few questions relating to some sounds in English.
>
> ...
>
> 3. Why does the IPA use the same letters for dental, alveolar and post
> alveolar sounds? As a result the English alveolar 't' and 'd' are
> written [t] [d] in IPA and the French dentals 't' and 'd' are also
> written [t] [d] in IPA. Both the sounds are pretty different.
>
> ...