Why does \uchyph=0 not work for me?

Question

Why does \uchyph=0 not work for me? It is in my preamble, but Istill get names of people hyphenated.

Is it a font issue?

I typeset with XeLaTeX.

---

Minimal example: try with XeLaTeX with and without fontspec:

\documentclass{article}
\usepackage{fontspec}

\begin{document}
\noindent
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.

\uchyph=0 %
\noindent
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
Some Textual Material.
\end{document}

Answer 1

I solved my problem.

I use several documents as input to my article. It seems I need to include \uchyph=0 in each of these separate documents. I always assumed that having uchyph in the preamble would make it effective globally.