Can people with neuropathy tell if a cup is hot before they burn their tongue?

Yes: Not likely that one would have tongue neuropathy. Much more if a concern that your hand may not sense heat properly and that they could be injured.

Most can: The typical location of most neuropathies starts in feet and goes up legs, the hands are involved later, but sensation to intense temperature is preserved over proximal limb and face and tongue usually remain unimpaired.