For the native Sony-Dictionaries, this depends on the region/version of T2 you own.
In general there are patches which will install all available dictionaries to be used with the Stock-Reader App.
see Amutins-page at the-ebook.org
rupors Page at the-ebook.org
With a rooted reader you can also use alternate reader-Apps like CoolReader
and alternate Dictionary-Apps like ColorDict