The prefix 'il' can be used. The complete word would be illogical.
illogical
The prefix In- can be added to numerable.
Speakable does not have a prefix as it is written. Speakable does have a suffix, -able. A prefix can be added to speakable - unspeakable.
There is no prefix but there is a suffix -ly added to the word passive.Prefixes are added to the beginning of a word eg happy/unhappy prefix is un-
The prefix 'im' can added to make the word impolite.
The prefix 'il' and or the suffix 'ly' may be used.
The root word of inconsequential is "sequential," which means following a logical order or sequence. The prefix "in-" added to "sequential" changes the meaning to "not following a logical order" or "not important."
The prefix that can be added to "please" is "dis-" to form "displease".
The prefix that can be added to the word "destructive" is "non-."
illogical
Impolite, unpolite
The prefix that can be added to appointment is "re-", forming the word "reappointment."
The prefix that can be added to "imperceptibly" is "un-".
The prefix added to "payment" to make it opposite is "non-."
Pre- is a prefix that can be added to the word monition.
The prefix In- can be added to numerable.
The prefix "non-" must be added to form the word "non-poisonous."