One reason I found Hilaire du Berrier’s Background to Betrayal dry and somewhat confusing is that it describes many ministers of government with strange names. Vietnamese names, written in the Vietnamese alphabet, are indeed quite strange to American English-speakers — but once you know the basics, it becomes much, much easier to “pronounce” Vietnamese in your head as you read along.
First, it helps to know that the Vietnamese alphabet — that is, how the Vietnamese use the Roman alphabet — is not based on French, as you might suppose, but on Portuguese, the language of early traders and Catholic missionaries. So the pronunciation of, say, Dien Bien Phu is pretty straightforward, and you can ignore your high-school French lessons, which might lead you to drop those trailing ns and to nasalize the preceding es.
Not everything is so straightforward for English-speakers though. Anyone who went to school with Vietnamese classmates knows that the Vietnamese name is Nguyen, and it is not pronounced nuh-GOO-yen. It’s much closer to nwin. That’s because ng is a common digraph in Vietnamese; those two letters together represent the single sound at the end of sing or in the middle of singer — but the Vietnamese use that sound at the beginning of many words, which we don’t do.
Another common digraph is nh, which makes sense if you know any Portuguese, because that’s the Portuguese way of writing ñ (Spanish) or gn (French, Italian). So the Minh in Ho Chi Minh is more like the mign in filet mignon.
The digraph ch is usually pronounced as in English; sometimes it’s just a hard c. The digraph kh is pronounced like ch in German. The digraph ph is pronounced as in English, like f. (I’m not sure why they don’t use f.)
The digraph th is — surprise! — not really a digraph the way it is in English; it’s pronounced like a t followed by an h; it is not pronounced as in thigh or thy.
Once you know the digraphs, you’re pretty safe, because most of the consonants are otherwise pronounced more or less as in English — but there are a few exceptions. For instance, Vietnamese has two forms of d, one which does sound like our d, but with a glottal stop in front of it, and one that sounds like either a z, in the northern dialect, or an English y, in the southern dialect. So Bao Dai sounds like bow die, with no surprises, but Ngo Dinh Diem sounds like no din yee-em; the second d sounds like a y.
In English, we soften a g in front of an e or i. In Vietnamese, they do the same, but it becomes a z, not a j. So Giap is zap.
In Vietnamese, an x is simply an s. An actual s can be either an s or an sh, depending on dialect.
As for all the accents, or diacritics, ignore them — unless you already speak a tonal language, like some form of Chinese. You have very little hope of learning tones by reading an article on the Net.
Anyway, I hope this explanation makes some strange names a bit less strange to you.