Maybe it's a silly question, but I suspect it isn't...

[sylvar]

Why is there no 'g' in 'theorem'?

Comments

[creases]

Where would the g go?

[regality3]

Theoregm, as in phlegm?

[creases]

Ah, okay. Well, the issue here is that there are different roots (and also different suffixes).

The g in words like "phlegm" or "paradigm" is part of the root (phleg-, heat; paradeig-, to exhibit beside), not the suffix. The suffix is -ma.

The root for "theorem" is theōr-, which means to behold. The suffix is -ēma.

Does that answer make sense?

[sylvar]

Yes, thank you. That was exactly the sort of answer I hoped to get.