XPath normalize-space() doesn't just trim !

Yes, It is true, the normalize-space function do more just trimming your text.
so:

<xsl:value-of select="  ABC     DEF  G   " />

Will return :
"AB DEF G"
So,Its real function is "Removes leading and trailing spaces from the specified string, and replaces all internal sequences of white space with one and returns the result"
So, be-careful when using it.