Comparative Grammar of the French, Italian, Spanish and Portuguese Languages
My new favorite book: Comparative Grammar of the French, Italian, Spanish and Portuguese Languages by Edwin A. Notley
Published in 1868!
400 pages of comparative goodness.
Verb conjugations (we really should bring back thou hadst and the T-V distinction in English!)
There’s even vocabulary at the end, though the words are not grouped thematically like they are in The Loom of Language.
I’ve also ordered A Comparative Practical Grammar of French, Italian and Spanish by Oliver Heatwole (1949) as well as Comprendre les langues romaines: Du français à l’espagnol, au portugais, à l’italien & au roumain by Paul Teyssier (2004), but I haven’t yet found a book like this for the Germanic languages.