Joop: Like Nigel says. The short form for Joseph; in Germany at Cologne: Jupp.
Kryskiw: approximately Kruiskiff, stress on the ui. The y stands for a sound like ü articulated backsides with the lips formed for an i, similar to the Turkish dotless i.
Spoelstra: Netherlands oe = long u (as in spoon)
Bjork: Scandinavian, there is a slash through the o = German ö
Only a few gifted people can pronounce the Umlauts ö and ü: Sandinavians, Germans, French and Turks. You others: don't grieve, you might follow the Russian example: ö like yo, and ü like yu (Europe).

There are some trollish yokels in this thread, Marion. Disregard them.
Orthography has its mysteries hidden deep in history; feel free to ask.

Wilfried