Why can't I read man pages? Where is nroff?

Nroff and troff aren't in the base installation. It is shipped as
part of AIX 3.2.5 but may not be installed. Use smit to install a
software package called txtfmt.tfs.obj from your 3.2.5 distribution
media.

In AIX 4.x, you need bos.txt.tfs.