Is there any alternative keyboard for Android HTC Desire 2.1 that supports English/Czech dictionary and easy way to switch between them?
You can install HTC_IME modified http://forum.xda-developers.com/showthread.php?t=624416 and make a gesture for cycling between EN / CZ.
I went for SwiftKey. Still waiting for Czech language dictionary though :-)
AnySoftKeyboard is a free application with many keyboard layouts and themes, and after installing it you may download langue pack for many languages, including the Czech one (or directly from Google Play - Czech for AnySoftKeyboard).
Czech dictionary from AOSP has more than 100,000 words. English langue pack with English dictionary is included by default.