There's no formal contraction of this word, but there's a common informal shortened version: add'l (sometimes used without the apostrophe, in which case it would be called an abbreviation). Other options are at
What_is_the_abbreviation_for_the_word_additional
No, "I'll" is a contraction of "I will" and is not a proper noun. It is a combination of the pronoun "I" and the auxiliary verb "will."
The word "weren't" is a proper contraction of the words "were not". E.g. "They were not going out" = "They weren't going out." "You were not there." = "You weren't there."
No, it's a contraction of 'I would' and is a part of proper grammar.
Weren't is the contraction word for were not.
The word ain't is a contraction of am not.I am going to use proper English every chance I get.
contraction for the word he is: he's
contraction for the word who is: who's
No, it's not a contraction. The word and is a whole word.
Contraction word for she will: she'll
There is no contraction for the word apostrophe. It's is a contraction of it is or it has.
Didn't is the contraction for did not.
No. A contraction cannot be a compound word.