Sacagawea is a Bonus

It was the winter stay of 1804-05 when God's biggest blessing came upon the Corps of Discovery.  It was then that Lewis and Clark decided to hire Toussaint Charbonneau, a French-Canadian trader who lived with the Hidatsa.  The Corps needed an interpreter.  The solution to the language problem wasn't optimal, but this is how it would work for the rest of their journey.

Lewis or Clark (or whomever) would say something in English.
A crew member, Drouillard would translate it into French for Charbonneau.
Charbonneau would translate it into Hidatsa for Sacagawea.
Sacagawea could then translate it in words and sign that the different tribal Indian Chiefs could understand.

Then, of course, the whole process would go in reverse for Lewis and Clark to response back.  Whew.  Sounds like the telephone game we used to play as kids where one whispers to another who whispers to another, etc.  Inevitably the message at the end rarely resembled what began.  But then, we were but children and known to intentionally mess it up.  This was deadly work Lewis and Clark were up to.  Or maybe I should say death-defying.

Wasn't it nice of Sacagawea to let me try on her buffalo robe?  We meet the nicest people in our travels!

God's blessing was in Charbonneau's wife, Sacagawea.  She was only 15 year old and six months pregnant.  Their soon-to-be-born son, Jean Baptiste, was a blessing, too.  With a woman and child along with them there would be less of a chance to be mistaken for a war party.  (Isn't it just like a man to call a group of themselves, who go off to behave like they were from Mars, a "party"!!!)

Even more than that, when the Corps desperately needed horses and there were seemingly none to be found, they happen upon an Indian settlement.  During discussions to acquire some horses, Sacagawea suddenly recognizes, amongst the chiefs gathered there, a long lost brother!  Actually, she was the one who had been lost for four years.  She was taken captive by a different tribe.

After that it was all hugs and kisses, and the Corps got their horses!  (They needed horses because they ran out of a navigable waterway, proving forevermore that there was no usable water passage to the Pacific Ocean.)
 

The Pacific Ocean - as seen from Kauai!