西班牙语中b和v的发音规则是怎样的

b和v的发音实际上是完全一样的,它们都是除了在m和n后以及在一个词的打头位置时发浊辅音以外(浊辅音BE,发音位置为喉咙;而与之相对应的清辅音是p,发pe,从口腔内发音),其它时候这两个字母均发闭嘴闭唇音V.其实那个浊辅音,西班牙人发的都是在BE和V之间的一个状态,但是对我们中国人可以要求不那么高啦,包括对我们专业的也没那么高要求,只要发浊辅音即好,但中国人是不分清浊辅音的,所以要相当注意,从喉咙发音.理论只能说这么多,最好是实践有人指导一下,希望可以对你有帮助.

在西班牙语里，b和v的发音是相同的。

当辅音字母b和v在停顿后的字首或m、n之后时，就发/b/音，发音时，双唇闭塞，形成阻碍，声带振动，气流冲开双唇爆破而出。

当辅音字母b和v在其余位置时，发/β/音，发音时，双唇微开，留出窄缝，声带振动，气流从双唇间的缝隙中摩擦而出，用力较弱。由于西语语速较快，当辅音字母b、v位于字中或词组内时，双唇未及完全闭合，即转发后面的音，发成了擦音，但应注意，双唇之间的缝隙不能过宽，避免把/β/发成美国英语舌后软腭半元音/w/的音。

正因为如此，西班牙语国家的人在学美国英语的时候，会把b音和v音这两个发音搞混淆。在美国英语中，这两个辅音字母的发音是有区别的。以下语音学描述，说明了这种区别。

The b sound, generally speaking, is a simpler sound that fewer non-native English speakers have trouble with. It is created when the top lip and bottom lip touch each other, blocking the air. When the lips open, the air is pushed out in a small "puff." We call the puff of air the "aspiration" of the sound.

In addition to the aspiration, another important aspect of the b sound is that it is voiced. A sound is voiced when the vocal cords vibrate during its production.

The v sound is a fricative. A fricative is created when air is forced out through a small opening in the vocal tract. The air is never completely stopped for a fricative. That means I can say the v sound for a long time, especially when it is at the end of a word.

I cannot do that with a b sound. I can only say it one time, then it is done.

The position of the bottom lip is very important when creating the v sound. To create the v sound, air is forced through a small opening is between the bottom lip and the bottom of the top front teeth. This happens when the bottom lip is tipped, very slightly, into the teeth. At the same time as the bottom lip is tipped close to the teeth, the vocal cords are also vibrating. The vibrating vocal cords make the v sound into a voiced sound.

希望我能帮助你解疑释惑。

不说课本上是怎么讲的
实际应用时基本都是这样：
词首和m、n后面发[b]
两元音之间发[v]
在词中且不是两元音间时各发各的音

至少我的老师都是这么发音的

发音是一样的
一般情况下是浊辅音，发[v],m n前面发清辅音[b]

b：在词首和n、m前发[b]，其它情况发[v]；
v：与b发音完全一样，在词首和n、m前发[b]，其它情况发[v]；