J.-Donat Langelier (became Langelier-Valiquette in 1963). Began ca 1915 at Pointe-aux-Trembles, Que. Continued ca 1930 in Montreal. Not a manufacturer. See Pratte.
Pratte Piano Co (La Compagnie de pianos Pratte), Montreal; fl 1889-1926, then linked to J.-Donat Langelier – Piano Building- The Canadian Encyclopedia
Hi my friend just moved to a new house where they left behind a piano by j.donant langelier were just wondering if there’s any value A’s they have no use for it what should they do would you be interested in it I found this # on the back 26054