Therein lies the crux of the issue, Yiddish speakers vs. Yeshivish Speakers.
And sometimes, even words that used are only used for one of multiple uses.
I might be completely off the base, but here's my theory:
In the English language the descriptive word for mother and it's honorific are two different words: Mother as in my mother, your mother, the mother of that family, vs. Mom (or mommy) is used when your talking to her or to a sibling about her.
On the other hand, in Yiddish, it is the same word Mamme that is used for both.
Therefore, when it comes to the Shvigger, amongst the English/Yeshivish speaking oilam, it is only a descriptive word. It is as strange to use as an honorific as saying to your mother, "Mother, please pass the salt."
But, for Yiddish speakers, there is no issue. They are used to having the same word for the descriptive and the honorific, so Shvigger can easily be used for both, Mother-in-law and Mommy-in-law. And perhaps, or rather likely, that is correct in the Yiddish language.
However, in Yeshivish it has only come to mean the descriptive word for Mother-in-law. So, there is no
perfect word for addressing a Shvigger as there is no word in Judeo-English that means Mommy-in-law.
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