#Perl, <s>47</s> 43 + 1 = 44 bytes

-4 bytes thanks to @Sunny Pun

Run with the `-n` flag.

    say!!/^(s(in?)?|co?|t(an?)?|ln?|log?|e)+$/i

I'm not sure this regex can be golfed any further, but I'll keep trying things.

[Try it online!](https://tio.run/nexus/perl#@1@cWKmoqB@nUayRmWevaV@TnG9fU6KRCGbn5AFxfrp9Taqmtop@5v//JYklJTmpJYk5qcX/dfP@6/qa6hkYGgAA "Perl – TIO Nexus")

I downloaded a dictionary file, and the longest word I found was 11 letters -- `tattletales`