Audio Demos on DE10 Standard not Working
From the schematic in the other answer:
The phone jacks J2 (LINE IN) and J3 (LINE OUT) with L,R,NCL,NCR,and GND is a THREE ring jack (L,R,GND) and has two switch connections which probably connect to L,R with no socket present.
The Mic In jack J1 is another three ring jack with the Mic connected to L, GND (and nothing on R). It DOES connect to the MBIAS pin on the WM8371 so it is all set to power an electret mic, assuming MBIAS is correctly enabled in the chip.
The most likely problem is inserting a 4 ring jack (T R1 R2 S) with the mic connected to R2 and S, into a 3 ring T R S socket with the mic connections on T and S.
The mic is designed to work with newer jack connections (both headphone channels and mic on the same plug, as used in smartphones) while the board was designed back in the era of multimedia PCs with three jacks : phone/line out, mic in, line in.
You'll need to find or make an adapter, or source an older style mic.