Complex sentence: Alice Vanderbilt Morris (1874-1950), born Alice Vanderbilt Shepard, was a member of the American Vanderbilt family who co-founded the International Auxiliary Language Association (IALA).
Split into simpler sentences: Alice Vanderbilt Morris (1874-1950), born Alice Vanderbilt Shepard, was a member of the American Vanderbilt family. She co-founded the International Auxiliary Language Association (IALA).