Hi! it seems there might me a bug in eTeX related to \savinghyphcodes. consider the following file, init.tex: ======================= \input plain \begingroup \language=1 \patterns{a1} \endgroup \begingroup \language=2 \savinghyphcodes=1 \lccode`\a=`\A \lccode`\A=`\A \patterns{a1} \endgroup \dump ======================= generate a format file with it: pdftex -ini -etex init.tex now, run the following: pdftex \&init test.tex where test.tex is: ======================= %\tracingall \hsize=1sp \language1 \noindent a bbbabbbabbbabbb bbbabbbabbbabbb {\language=2 bbbabbb}. bbbabbbabbbabbb bbbabbbabbbabbb \noindent a bbbabbbabbbabbb bbbabbbabbbabbb {\language=2 bbbabbb} bbbabbbabbbabbb bbbabbbabbbabbb \bye ======================= there are two paragraphs in the text, the only difference is that the first one has a period after a group. in the first paragraph, however, eTeX does not find any hyphenation points after the group, but it does find them in the second paragraph where there is no dot. this behavior looks like a bug. in particular, when i try to use the \savinghyphcodes feature, i get no hyphenation in the rest of a paragraph after temporarily switching to some language for which there was a \savinghyphcodes. i don't know why it is triggered by the presence of a period, - i just noticed that in the absense of a period (or maybe any other non-space character) the bug disappears; but if the group is followed by a non-space character such as a period, the bug is present. Best, v.