In the Apple anniversary edition of this week in tech, Andy Hertzfeld said
that almost all the original Mac apps were written in pure assembler, as the
compilers for the 68000 weren't that advanced at the time, and they needed
to wring out every last bit of performance from the platform. I'd assume the
same would be true for the Lisa apps.
It's a good episode to listen to, if you're into early Apple lore.