- Grammar of the language of the Lenni Lenape or Delaware Indians
- Vergleichende Grammatik Des Sanskrit, Zend, Griechischen, Lateinischen, Litthauischen, Altslawischen, Gothischen Und Deutschen, Volumes 1-2
- A Comparative Grammar of the Sanskrit, Zend, Greek, Latin, Lithuanian, Gothic, German, and Sclavonic Languages, Volume 2 - Primary Source Edition
- Grammaire Compara(c)E Des Langues Indo-Europa(c)Ennes. Tome 1 (A0/00d.1866-1875)
- Grammaire Compara(c)E Des Langues Indo-Europa(c)Ennes, (A0/00d.1885-1889)