Dear Claudineraciti,
You ask the question: 鏠an you use the possessive ´s with the personal subject pronoun I?�
For example:
岞y mom and I ´s cat�.
The answer is NO.
𨧻𠏋 cat� is as bad as saying 㛝ou𠏋 cat� 鐈e𠏋 cat� 廍he𠏋 cat� 㜁e𠏋 cat� 孏hey𠏋 cat�.
When I teach possession, using 𩾷he apostrophe�, I teach that the apostrophe represents the word 㺸f�.
岞aria𠏋 house� = 孏he house of Maria�.
孏he dog𠏋 name is Rex� = 孏he name of the dog is Rex�.
岞y mother𠏋 hat is blue� = 孏he hat of my mother is blue�.
鎽ohn𠏋 bicycle is fast� = 孏he bicycle of John is fast�.
孏he man𠏋 car is expensive� = 孏he car of the man is expensive�.
孏he men𠏋 car is expensive� = 孏he car of the men is expensive�.
孏he student𠏋 College is modern� = The College of the student is modern�.
孏he students� College is modern� = The College of the students is modern�.
岞y mom and I𠏋 cat� = 岞y mom𠏋 cat and I𠏋 cat� = 孏he cat of my mom and the cat of I� = ungrammatical.
If I were asked: 㜁hat would you say?� it would depend on the context of the conversation.
㜁hose is this cat?� 𨧻t𠏋 ours! It belongs to my mother and me�.
𨧻s this your cat?� 㛝es, it𠏋 ours, my mother𠏋 and mine�.
㜁hat is this black thing in the corner?� 𨧻t𠏋 my mother𠏋 and my cat�.
It would be possible to give a variety of suitable answers, but
岞y mom and I ´s cat�
is NOT grammatically acceptable.
Les