Decasylable or Decasyllable: How To spell?

The word Decasylable is misspelled against Decasyllable, meaning "A line of ten syllables."

Decasyllable has double "ll" is mispronounced as "l"
Remember double 'LL' in between the strings decasy & able which should not be misspelled with single 'L'
Wrong Spelling:  decasy-l-able 
Correct Spelling:  decasy-ll-able 
Explore spell check of Decasyllable to spell without errors.