Right in the beginning of her speech, Le Guin tells a very obscure Greek quip:

I know there are men graduating, and I don't mean to exclude them, far from it. There is a Greek tragedy where the Greek says to the foreigner, "If you don't understand Greek, please signify by nodding." (2-3)

There's a couple of ways you could interpret this allusion. One way is to take it as a joke. Like, if he can't understand Greek, how would he know how to nod? Another way she might've intended us to take the reference is to illustrate the fact that sometimes, communication is harder than it seems; especially when conversing with someone who has no way to relate to your own experiences.

She also mentions that women have lived in "the valley of the shadow", which may sound familiar to anyone who's ever been to Sunday school. In the well-known bible passage, Psalm 23 reads, "though I walk through the valley of the shadow of death, I will fear no evil, for you are with me." It's kind of hard to tell whether she makes this allusion on purpose or not: she is using the phrase to describe the fact that women inhabit the deep/dark aspects of life, like weakness, illness, and the irrational. Death can certainly be considered a dark certainty in human life, but it's not clear whether she draws this comparison on purpose, or whether it's a fortunate turn of speech.