XSLT for each letter in a string

Question

I\'m writing an XSLT transformation (for XSL-FO), and need to repeat something for each letter in a string value, for example:

If string is stored in MyData/My

Answer 1

Several XSLT 1.0 solutions have been posted (since that is what the original poster needed). For comparison, though, here is how this could be done in XSLT 2.0 using xsl:analyze-string: