--> Decasyllabic has double "ll" is mispronounced as "l"
Remember double 'LL' in between the strings decasy & abic which should not be misspelled with single 'L'
Wrong Spelling:  decasy-l-abic 
Correct Spelling:  decasy-ll-abic 
Find more wrongly spelled words of Decasyllabic to spell it well.