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.
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