Merriam-Webster's Official Scrabble Players Dictionary includes approximately 100 two letter scrabble words. Jo is the only 2 letter word in the dictionary starting with the letter j.
Juniper
Juice?
Jeep stalled
A J Food you can eat is Jam. or Jiffy Peanut Butter?
A four letter word starting with J is jump or joke.
joust
jamoke
Fuji
JunkJambJustJoinJail
java
Possibly 'jurisdiction.'
junta, jelly, joust
joyful
jazz
i dont know the answer either!
June