Shin and Tav Exchange, ש"ת

Anyone familiar with gemara knows that often the hebrew ש is replaced in aramaic with a ת (e.g. תורא, תנינן, תלגא )

In russian as well the two switch, depending on whether talking formal or informal.

Formal speech (vui) ends with ת (e.g. You want, вы хотите , vui chatite) whereas the informal (tei) is ש

[Don't know the spelling but transliterated it's something like "tei choichish"]

Could they actually be opposites of one another? The ת denoting distance (ארמי) whereas the ש used for closeness (עברי)?

See הקדמת הזהר as well where the ת is used ultimately to judge and kill צדיקים whereas the ש is seemingly perfect if not for the fact that it is accompanied by קר to allow for שקר...

[Note also the peculiarity of the ש on our תפילין של ראש vs the ת on their foreheads in יחזקאל ט

והתוית תיו על מצחות האנשים הנאנחים והנאנקים על כל התועבות הנעשות בתוכה ]

No idea what I'm talking about really but just food for thought for now.