Speakable does not have a prefix as it is written.

Speakable does have a suffix, -able.

A prefix can be added to speakable - unspeakable.

The adjective form of "speak" is "spoken."

It is an acronym as the letters LOTE forms a speakable word (LOAT) AND each letter represents another word. FBI is not an acronym, even though it has each letter representing something, as it is not a speakable word.

Speech is the noun form of speak, and speakable is the adjective form of speak.

You would normally speak to a Mac to make it do something by turning on the Speakable Items in the Speech Recognition section of the Speech System Preferences. You can create an AppleScript to respond to your finger clicking input and do some action.