Aus dem TeXbook > TeX uses the \lccode \\lccode to convert each letter to lowercase form; a word-to-be-hyphenated will match an entry in the exception dictionary if and only if both words have the same lowercase form after conversion to lowercase. Folglich reicht einmal kleinschreiben. Dann allerdings \hyphenation{pneu-mo-noul-tra-micros-co-pic-silico-vol-cano-conio-sis}

Aus dem TeXbook > TeX uses the \lccode to convert each letter to lowercase form; a word-to-be-hyphenated will match an entry in the exception dictionary if and only if both words have the same lowercase form after conversion to lowercase. Folglich reicht einmal kleinschreiben. Dann allerdings \hyphenation{pneu-mo-noul-tra-micros-co-pic-silico-vol-cano-conio-sis}