Why does the B in the word absorb change to P when the suffix "tion" is added?
Absorb + tion = absorption and not absorbtion.
The answer to this question is here:
Question: Why does the B in absorb change to a P in absorption?
Answer: Too long but here is the main part:
Voicing Assimilation is the technical term for what happened here.
This was an existing question and answer but my question is different from that one so it's not a duplicate.
My question is:
*Why does the B change to P in the root word but the suffix remains the same. Why didn't the suffix "sion" attach to the word absorb? It could have been absorbsion.
If we have to keep the alternating sounds the same, then B and zh (of sion) are both voiced.
In most words, the sounds in the root words remain the same and the suffix is changed.
Is there any rule that determines the addition of "tion" and "sion"? When should we use "tion" and when "sion"?