Can KudoZ askers direct their questions to specific site users?

Yes. When posting a KudoZ question, ProZ.com (paying) members are given the option to restrict their KudoZ questions by:

• Team membership (private questions)
• Native language
• Language pair emphasis (working or interest)
• Field (specialty, working, or interest)
• Membership (Only ProZ.com members may answer)

If the asker selects the option "Only ProZ.com members may answer" when posting his/her question, the "Answer" button will not be visible to non-members and the following message will show to them:

The asker has directed this question specifically to ProZ.com users who:

... are ProZ.com members (You do not appear to be)

Join ProZ.com > 

If the asker specifies a restriction connected with native language, level of expertise in the specified language pair or level of expertise in the field, those that do not meet these criteria will be informed of this, but still invited to post an answer:

The asker has directed this question specifically to ProZ.com users who:

... have expressed interest in this pair (You have)
... report a "specialty" level of expertise in the subject field (You have not) [Edit]
... are native speakers of Tonga (Nya) or Nzima (You have not reported that you are) [Edit]
Although you do not meet the criteria, you may suggest a translation if you like