\def\fifo#1{\ifx\ofif#1\ofif\fi\process#1\fifo}
\def\ofif#1\fifo{\fi}

\def\loc#1#2{%locate #1 in #2
  \def\locate##1#1##2\end{\ifx\empty##2%
    \empty\foundfalse\else\foundtrue\fi}%
\locate#2.#1\end} \newif\iffound

\def\process#1{\uppercase{\loc#1}{AEIOU}\iffound{\bf#1}\else#1\fi}