I saw this in a PowerPoint document.

Problem:
This adjective is misspelled.

Explanation:
I believe that the misspelling of the adjective “accessible” is mostly due to the common mispronunciation — as “accessable” — of that adjective.

Other adjectives that use “ible” instead of “able” include “visible” and “horrible”.

The suffix “ible” is a variation of the suffix “able”; most people use memorization to know which suffix to use.

For fun, I searched Google for each of the following words (with the quotation marks to avoid hyphenated forms) and got about the indicated numbers of matches:

• “accessible” — 130,000,000 matches
• “accessable” — 2,170,000 matches

This tells me that Web authors have written the word correctly vs. incorrectly by a ratio of 59.9:1, which is good, but the fact that the Web contains more than two million instances of “accessable” is disappointing.

Solution:
“Accessible”