Why This is cannot be written as This' or This's?

Answer 1

The word "is" is a form of the verb "to be." When you add an apostrophe s ('s) to a word, it is to show ownership, not to conjugate the verb "to be." For instance "This is the dog's bed." means the bed belongs to the dog. An s apostrophe (s') is used to show ownership when the noun is plural, such as "These are the childrens' clothes." The word clothes is plural and since it already ends with an s, you would use an apostrophe after the s to show ownership. This's (as a conjunction of this is) seems perfectly logical. After all, he is is contracted as he's. It's just not an accepted usage in modern English. It may be that some day it will become "correct", but not now. On the other hand, it may never be used, since the conjunction of the two s's makes it difficult to understand when verbalized. This'doesn't have an analogy with any existing spelling. If you're thinking of the possessive use for the apostrophe, well, this isn't possessive, is it? So I think it's unlikely that this contraction will ever be used to mean this is.