you could - BUT the wires are very fine, thin insulation etc. It would be a very 'fiddly' job.
Strip the wires back and identify the (common) ground, and left and right channel - then you can fit an in-line 3.5mm socket to them.
You need to work out how the mechanics work - as not to put too much stress on the wires.
Use high impedance earphones and you will cause no problems.
When soldering take care not to melt trough the insulation of the audio wires