Bowie – As in David, like the frontiersman and knife, the bow as in bowtie rather than the bough of a tree.
Van Gogh – It doesn’t end in an ff sound, it’s a gutteral gh.
Mandelbrot – Set man, Benoit told the world to pronounce it to rhyme with handle-not
Moog – As in Mini Moog, Robert its inventor rhymed it with vogue
Dvorak – Tech writer John C Dvorak pronounces his name duh-vor-ack, not vor-jak
Gif – As in the graphics interchange format, should be pronounced jiff with a soft g not a hard G, according to its inventor Steve Wilhite
Trump – is actually pronounced trunt
Next up British placenames: Llanelli (th-lan-eth-lee), Loughborough (luff-bruh), Ruislip (rye-slip), Happisburgh (haze-bruh), Leicestershire (lester-shuh), Beaulieu (byoo-lee), Towcester (toaster), Alnwick (ann-wick), Islay (eye-la), Mousehole (mow-zul), Belvoir Castle (beaver castle), Gotham (goat-ham), Godmanchester (gumster) etc…