Does anyone know how long it takes to travel by train from berlin germany, to toulouse, france?

Roughly 17 hours!

You can get there in less than 15 hours if you leave at
4:33 am to Frankfurt arr. 8:44/dep. 9:01 to Paris Est - arrive at 12:49, take the Metro to Montparnasse station in Paris, then the TGV train to Toulouse, dep. 14:10/arr. 19:22.
Or you could take a number of other combinations that take between 15 and 19 hours with changes.
One comfortable combo is the night train from Berlin to Paris,
dep. 21:34/arr. Paris Nord 9:14, then the Metro to Paris Austerlitz, and from there to Toulouse dep. Paris at 10:17; arr. 16:33.
http://www.oebb.at/en
For toulouse, choose "Toulouse-Matabiau"
That's the main station.

You can probably fly more cheaply, like on germanwings from Berlin to Bordeaux, then a train from Bordeaux to Toulouse..