>I have noted a number of theoretical posts on shewa, but have rarely
>found any concrete guidance, the form of which a student can take and
For practical purposes, the single rule, "pronounce the schewa only
when you have to" works very well. In a context like YIKh'TOV, people
will naturally not pronounce the schewa, while in contexts like
"hal'lu," they will tend to pronounce it.
Similarly, transliterating every schewa with an aprostrophe will give
useful guidance to those trying to pronounce Hebrew.