Misc: what is the artificial international language invented in 1887 called?

Questions

"If we cannot now end our differences, at least we can help make the world safe for ---------."- John Fitzgerald Kennedy?

"If we don't ----------, we don't grow. If we don't grow, we aren't really living."- Gail Sheehy?

"The harder you --------, the luckier you get."- McAlexander?

"If we don't ----------, we run the risk of failure."- J. Danforth Quayle?

"The hardest job kids face today is learning ------------ without seeing any."- Fred Astaire?