I guess that "Gerlt" is a bit hard for some people to pronounce.  When you've had that as your name your whole life, it doesn't seem so tricky.  I've heard a wide variety of failed attempts to get it right.  I've also seen many "corrections" for the way it is spelled, all of which assume we left out some vowels somewhere.  Most of the mispronunciations also involve adding an extra vowel and a syllable or two.  "Gerrit", "Gerlit", and "Geralt" are pretty common attempts.

"Gerlt" is actually pronounced exactly as it is spelled, 5 letters, one syllable, kinda like "girl" with a T sound at the end.  No, not "Gerlty", either. 

If that doesn't make sense, here's how we Gerlts say it:  Say "Gerlt"

If those consonants at the end twist your tongue too much, just do what we do here for convenience and call us "GT" !