What 2 words do you choose? How do you decide?
For example, do he learn hurricane instead of like? Hurricane not used in communication often but like is. Like would be 'key' word for me to teach him.
For me, I sign 'key' words to boyfriend. Every time I speak that word I repeat the sign. If he make mistake I just show him correct sign.
So, he now knows these words:
Me
You
Why?
What?
Understand/do not understand
Like/do not like
Happy/not happy
I love you
Couple/not together
You and Me (different from you/me) sorry
Thank you
Good/not good (bad)
Something
Every
Everything
Word
Lady
Father
Mother
Girl
Boy
Eat
Hungry
Fine
Want?/do not want
Have/do not have
See
Look-at
Come-to
Go-to
Earth
World
People
Know/don't know
Hard
Stop
Look-at
Fireworks
Wow
Amazing
Rain
Tell-me
Time
Etc., etc.
As he become better I add new word to vocabulary. Simple words help him to form simple ASL communication.
Him: Eat what want?
Him: You amazing! Wow! 
