· Dropping the second L in a prefix:
If a prefix ends with a double L is added to another word to form a compound word, the double L becomes a single L. For Example:
All+most= almost, All+ready=Already, All+right=Already
All+though=Although, All+ways=Always, Full+Fill=Fulfil
Full+some=Fulsome, Skill+full=Skilful, Well+come=Welcome.
· Full or Ful:
The only word ending full that takes a double L is ‘full itself.’ Otherwise, there is always a single L—or –ful when it is the last syllable of a word of two or more syllables. For example, there are the following adjectives:
Bashful fitful mournful successful
Beautiful frightful painful tearful
Careful fruitful peaceful thoughtful
Colourful grateful pitiful useful
Similarly, ‘till’ with the prefix becomes ‘until’
· Keeping both is when adding –ly to words ending in L.
There are always two Ls if the suffix –ly is added to a word ending in L. If an –ly is added to any of these adjectives ending in –ful in order to form adverbs, they take –fully ending, as follows:
Accident+ly: Accidentally, Actual+ly: Actually,
Cool+ly: Coolly, Cruel+ly: cruelly, Cynical+ly: cynically,
Final+ly: finally, Total+ly: totally, usual+ly: usually.
When a word does not end in L then generally we follow the straight forward rule of adding –ly when converting an adjective to an adverb.
Complete+ly: completely, Definite+ly: definitely, Extreme+ly: extremely, Friend+ly: friendly, Interest+ly: interestingly.
Let’s discuss some exceptions to the general straight forward rule of adding –ly.
· When the –ly suffix is added to a word or stem ending Y, this latter Y changes to I. Thus…
Busy+ly: Busily, Crazy+ly: Crazily, Fancy+ly: Fancily, Hungry+ly: hungrily, Ready+ly: Readily, Steady+ly: Steadily.
· Adding Ly after IC:
A word ending in –Ic adds –ally, instead of plain –ly, to become –ically.
Analytic+ally: Analytically, Atheletic+ally: Athletically. Automatic becomes automatically, fantastically, scientifically, basically, frantically, comically, historically, statistically.
Public becomes publicly not publically as this is an exception.
· -ble becomes –bly, and –ple becomes –ply.
Adjectives ending in-ble changes the –e to –y to achieve an –ly adverbial ending. This also rule also applies in case of –ple ending.
Ample- Amply, Capable-capably, durable- durably, favourable- favourably, Humble becomes humbly.
Exceptions: Truly, Duly, Wholly, Dully, Fully,