UK TeX FAQ -- question label badhyph

### Improper `\``hyphenation` will be flushed

For example

    ! Improper \hyphenation will be flushed.
    \'#1->{
           \accent 19 #1}
    <*> \hyphenation{Ji-m\'e
                            -nez}

(in Plain TeX) or

    ! Improper \hyphenation will be flushed.
    \leavevmode ->\unhbox
                          \voidb@x
    <*> \hyphenation{Ji-m\'e
                            -nez}

in LaTeX.

As mentioned in “hyphenation failures”, “words” containing `\``accent` commands may not be hyphenated. As a result, any such word is deemed improper in a `\``hyphenation` command.

Hyphenation happens as paragraphs are laid out; by this time, TeX knows what font is used for each glyph; thus it knows the encoding being used. So the solution to the problem is to use a font that contains the accented character; doing this this “hides” the accent from the hyphenation mechanisms.

For LaTeX users, this is quite an easy task; they select an 8-bit font with the package, as in `\``usepackage[T1]{fontenc}`, and accented-letter commands such as the `\``’``e` in `\``hyphenation{Ji-m`\``’`e-nez}` automatically become the single accented character by the time the hyphenation gets to look at it.

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=badhyph