The bisaiguë isn't used freehand. Both hands are used, one on the handle and the other on the shaft to guide it. I think that the french would use a tarière (an auger) to pre-pierce the hole and then the bisaiguë would be used to clear the remaining material. I've seen references that imply as much, but nothing that clearly states it.
I wondered why it was that the French traditionally worked so low, but it just occurred to me; a standard practice here was to draw the layout on the ground at 1:1 scale and to lay the timbers over the top. Given this methodology, the ability to work at ground level comfortably would explain the evolution of such a long tool.
