[Newbies] Dialect class

[xyz 42]

Hello!

I am missing the Dialect class (I typed Dialect in workspace and said
browse).  Is this part of Squeak or is this part of some package?  If
it is part of some package, how can I find out which package?

I am using the web image (3.10.2) here
http://damien.cassou.free.fr/squeak-dev.html.

TIA.