In an other post on this website, this suggestion was given :
When you are typing a text message (go to text, add a number to receive the message, then go to the message field and start typing your message) you can hold FN and SPACE BAR in. This will show you the available dictionary languages.
This way, i succeeded in changing from French to English.
Unfortunately, i could not select Dutch, altough my phone is set for DUTCH as being my own language. Country setting remains FRANCE, altough Dutch is not an official language in France.
I think the ROM should be updated with better and more complete country settings or a Dutch language pack should be added. Please make an update, HTC..