I have no snow to shovel, but I hope that does not invalidate my suggestion.
Surely the TEI already has a suitable mechanism for this: <term> and
<gloss>. I would say that a codified symbol representing another word falls
within the remit of this. I would suggest setting up a gloss-term list in
the Header or even the backmatter if it is considered worth exposing to the
reader, retaining the text as the original, and using corresp to align the
individual occurrences. Something like:
<p>My mother-in-law is <term corresp="t1">from Tewkesbury</term>.</p>
<item><term id="t1">from Tewkesbury</term><gloss target="t1">thick as a
This preserves the integrity of the original, and provides a mechanism for
either performing a direct term-to-gloss substitution in any output, or
leaving the text intact and outputting a glossary. In instances where the
gloss has actually been written in, you could also provide the gloss within
the text, thus:
<p>My sister-in-law <term id="t2">likes a laugh</term><note place="above"
resp="secretary1"><gloss target="t2">drinks like a fish</gloss></note>.</p>
As a alternative, one could also argue that a codified term is a referring
string to the actual term, and use <rs> instead.