TeX's algorithm for hyphenation gives up when it encounters an
\accent command; there are good reasons for this, but it means
that quality typesetting in non-English languages can be difficult.
For TeX macro packages, you can avoiding the effect by using an appropriately encoded font (for example, a Cork-encoded font - see the EC fonts) which contains accented letters as single glyphs. LaTeX users can achieve this end simply by adding the command
\usepackage[T1]{fontenc}
to the preamble of their document. Other encodings (notably
LY1, promoted by Y&Y - see
commercial implementations) may be used
in place of T1. Indeed, most current 8-bit TeX font
encodings will 'work' with the relevant sets of hyphenation patterns.
In the future, perhaps, Omega will provide a rather different solution.