Tradeable or Tradable

[Danny]

Hello:

"Knowledgeable" is spelled, as far as I know, with the second "e";
however, some dictionaries accept the spelling without the second "e"
as an alternate.

"Tradable" is the primary spelling, according to all the dictionaries
I've checked, whereas "Tradeable" is the secondary and is rejected as
a proper spelling in some dictionaries.

I am confused because it seems that the "ea" rule for "knowledgeable"
would apply to "tradable" as well; however, there may be dissimilarity
between the different sounds created after an "ea" or the lack
thereof.

Any information you could add to my understanding, or
misunderstanding, would be greatly appreciated.

Thanks,

| Danny |

[jaos...@asu.edu]

The silent "E" rule applies. If the suffix starts with a vowel the "E" is dropped. If the suffix starts with a consonant the silent "E" remains.
Jerry