To me, a "cunning linguist" is the foundation of a good lover. If he doesn't want to give oral sex, and good oral sex, we don't just not have a future — we don't have a present.
But, based on conversations with men friends and readers, not all women are this way. Indeed, some won't allow their lovers to go down on them. In a few cases, she will give good head — but doesn't want to receive.
Over the years, I've had many conversations with girlfriends about this topic. It's led me to offer these reasons why these women are reacting the way they do.
Some are very sexually repressed. They were taught by their mothers that "you pee down there," and their private parts are somehow dirty and off-limits. Certainly to a man's (or woman's) mouth.
Another reason is control. Nothing is more intense than an orgasm from oral sex. Some of these women have told me they don't want to let go that much. They're content with less-intense vaginal orgasms (although mine are explosive, a rarity) or no orgasm at all. These women aren't very highly sexed to begin with, to paint with a broad brush.
A good many had bad experiences with men who went down on them. The men were inept or selfish lovers. When I have an orgasm from a man's tongue-worshipping, I want him to know how to sense how much is too much, or too little — and this changes over the course of the oral love-making.
Finally, some women simply aren't very responsive. For a variety of reasons, they either can't have orgasms or never learned how. The background here can range from the psychological to physical causes.
If your girlfriend fits into these categories, my advice would be to run away. It won't get better, especially if you like the full menu of sex. If she's resistant to receiving oral sex, there will likely be other no-go zones and the sex will die off once she has your commitment.
If she's the love of your life, be prepared to be patient. Try to get her to talk about why she doesn't want oral sex. Can you live with it if she doesn't? I couldn't. But everyone's different.