LPC Formant Estimation: Why resample? The Burg algorithm implemented in PRAAT for formant estimation also works via LPC. First the sound is resampled to a sampling frequency of twice the value of maximum formant. Then a pre-emphasis is applied and finally, PRAAT applies a Gaussian like window to compute linear prediction coefficients through the Burg algorithm.

I understand that pre-emphasis is helpful for formant extraction by LPC since the human voice is not spectrally flat, but am confused about why Praat is resampling.
https://github.com/praat/praat/blob/bac77ad76481c65703ade8d7ddb190e9d67048d6/fon/Sound_to_Formant.cpp#L381
You want to resample down to alias frequencies higher than your maximum desired formant.
If you understand aliasing in the z-transform and the transfer function of a system then this should be obvious.