There are 18 words that start with 'chall'.
| challa | chally | 
| challah | challas | 
| challie | challis | 
| challot | challahs | 
| challies | challoth | 
| challenge | challises | 
| challenged | challenger | 
| challenges | challengers | 
| challenging | challengingly | 
Note: These 18 words that start with 'chall' are found from the USA & Canada version of the tournament Scrabble word list.